Check what the clocks said in 21 places, 1870 to 1919.

The files

curl -sO https://zodiacs.org/developers/time-atlas/0.1.0/data/places.json
shasum -a 256 places.json

git clone https://github.com/zodiacs-org/engine.git
cd engine && git checkout 7307665bdbc432269fdac006104f661be16000bc
node atlas/tools/check.mjs
node atlas/tools/compare-tzdb.mjs --check

Licence and attribution

How to cite

Zodiacs.org historical time atlas, version 0.1.0, https://zodiacs.org/developers/time-atlas/ (its files are listed in https://zodiacs.org/developers/time-atlas/0.1.0/files.json), from https://github.com/zodiacs-org/engine/tree/7307665bdbc432269fdac006104f661be16000bc/atlas, licensed CC BY 4.0.

Corrections

The comparison with tzdb 2025c

Explanations

Sources

1. fr-jo-1916-06-11-decree Décret fixant l'application de la loi du 9 juin 1916 (10 juin 1916), 1916-06-10, Président de la République, sur le rapport du ministre de l'instruction publique, des beaux-arts et des inventions intéressant la défense nationale, Journal officiel de la République française, 11 juin 1916, p. 5134, col. 1, art. 1er. Source

2. fr-jo-1917-03-21-decree Décret relatif à l'avance de l'heure légale pendant la période d'été (20 mars 1917), 1917-03-20, Président de la République, sur le rapport du ministre des travaux publics, des transports et du ravitaillement, Journal officiel de la République française, 21 mars 1917, p. 2274, col. 1, art. 1er and 2. Source

3. fr-jo-1918-03-01-decree Décret sur l'avance de l'heure légale (28 février 1918), 1918-02-28, Président de la République, sur le rapport du ministre des travaux publics et des transports, Journal officiel de la République française, 1er mars 1918, p. 2016, col. 2, art. 1er and 2. Source

4. fr-jo-1919-02-11-decree Décret avançant l'heure légale de soixante minutes dans la nuit du 1er au 2 mars et rétablissant l'heure normale le 5 octobre (9 février 1919), 1919-02-09, Président de la République, sur le rapport du ministre des travaux publics et des transports, Journal officiel de la République française, 11 février 1919, p. 1604, col. 1, art. 1er and 2. Source

5. fr-petitparisien-1916-09-30-public-clocks Aujourd'hui la journée sera de 25 heures ! C'est la nuit prochaine qu'il faudra retarder les pendules d'une heure, 1916-09-30, Le Petit Parisien, Le Petit Parisien, 30 septembre 1916, p. 1, col. 5, the paragraph before the one quoted in fr-petitparisien-1916-09-30. Source

   All public clocks, the railways', the post offices', the State's, the départements' and the communes', were to be set back an hour at 01:00 in the night of 30 September to 1 October 1916.

6. fr-petitparisien-1916-09-30 Aujourd'hui la journée sera de 25 heures ! C'est la nuit prochaine qu'il faudra retarder les pendules d'une heure, 1916-09-30, Le Petit Parisien, Le Petit Parisien, 30 septembre 1916, p. 1, col. 5. Source

7. fr-petitjournal-1916-09-30 Une heure pour rien cette nuit en chemin de fer, 1916-09-30, Le Petit Journal, Le Petit Journal, 30 septembre 1916, p. 2, col. 5. Source

8. fr-petitjournal-1917-10-06 Attention ! ce soir, retour à l'heure d'hiver, 1917-10-06, Le Petit Journal, Le Petit Journal, 6 octobre 1917, p. 1, col. 2. Source

9. fr-petitparisien-1917-10-07 Le retour à l'heure normale s'est effectué cette nuit, 1917-10-07, Le Petit Parisien, Le Petit Parisien, 7 octobre 1917, p. 2, col. 1. Source

10. fr-petitparisien-1918-10-04 Demain retour à l'heure normale, 1918-10-04, Le Petit Parisien, Le Petit Parisien, 4 octobre 1918, p. 2, col. 2. Source

11. fr-petitjournal-1919-10-05 Heure d'hiver : heure normale (note of the sous-secrétariat d'État aux Transports, 4 October 1919), 1919-10-05, Le Petit Journal, printing a note of the sous-secrétariat d'État aux Transports, Le Petit Journal, 5 octobre 1919, p. 1, col. 3. Source

12. fr-senat-1891-02-17-restoration Sénat, séance du 17 février 1891: 1re délibération sur le projet de loi ayant pour objet l'adoption de l'heure, temps moyen de Paris, comme heure légale en France et en Algérie, 1891-02-17, Sénat, Journal officiel de la République française. Débats parlementaires. Sénat, 18 février 1891, p. 72, col. 2 (speech of the commissaire du Gouvernement, M. Faye, president of the Bureau des longitudes, named on p. 71). Source

    Since the Restoration the legal time of every place in France had been its own local mean time.

13. fr-senat-1891-02-17-brest Sénat, séance du 17 février 1891: 1re délibération sur le projet de loi ayant pour objet l'adoption de l'heure, temps moyen de Paris, comme heure légale en France et en Algérie, 1891-02-17, Sénat, Journal officiel de la République française. Débats parlementaires. Sénat, 18 février 1891, p. 72, col. 1. Source

    In Brest only the station clock showed Paris time; the town's other public clocks kept local time, 27 minutes behind.

14. fr-jo-1891-03-15-law Loi ayant pour objet l'adoption de l'heure temps moyen de Paris comme heure légale en France et en Algérie (14 mars 1891), 1891-03-14, Président de la République (Sénat et Chambre des députés), Journal officiel de la République française, 15 mars 1891, n° 73, p. 1233, col. 3. Source

15. fr-jo-1870-11-06-promulgation Décret relatif à la promulgation des lois et décrets par l'insertion au Journal officiel, 1870-11-05, Gouvernement de la défense nationale, Journal officiel de la République française, 6 novembre 1870, n° 306, p. 1, col. 1, art. 2. Source

    Laws bind in Paris one clear day after promulgation (their printing in the Journal officiel), and elsewhere one clear day after the Journal reaches the seat of the arrondissement.

16. als-snn-1918-11-21-bekanntmachung Bekanntmachung, betreffend Einführung der französischen Zeit an Stelle der mitteleuropäischen (Straßburg, den 20. November 1918), 1918-11-20, Der Bürgermeister der Stadt Straßburg (Peirotes), Straßburger Neueste Nachrichten, Nr. 272, Donnerstag, 21. November 1918, p. 1, col. 2. Source

    At noon on 21 November 1918 the city's public clocks were to be put on French time by setting them back to 11:05.

17. als-elsasser-1918-12-16-pariser-zeit Pariser Zeit (reader's letter, Straßburger Stadtchronik), 1918-12-16, Der Elsässer, Der Elsässer (Straßburg), 16. Dezember 1918, p. 2, col. 4. Source

    A reader writes that the clocks were set back 55 minutes on 21 November and that Strasbourg's station clock runs five minutes behind the public clocks.

18. als-jh-1919-02-28-railways Die Sommerzeit, 1919-02-28, Journal de Haguenau, Journal de Haguenau: indicateur général du Bas-Rhin, 28 février 1919, p. 2, col. 1. Source

19. als-snn-1892-03-31-mez Mitteleuropäische Zeit (Straßburg, local news), 1892-03-31, Straßburger Neueste Nachrichten, Straßburger Neueste Nachrichten, Nr. 77, Zweites Blatt, Donnerstag, 31. März 1892, Zweites Blatt, first page (Gallica view 5), col. 2. Source

    The Ministry for Alsace-Lorraine ordered Mid-European time to be introduced generally as local time from 1 April 1892; municipal authorities were to correct the public clocks that day, by the public clock of the nearest railway station.

20. mos-lz-1892-03-29-city Mitteleuropäische Zeit (Metz, local news), 1892-03-29, Lothringer Zeitung, Lothringer Zeitung und amtliche Nachrichten (Metz), 29. März 1892, p. 3, col. 2. Source

    The city's clocks, the cathedral's among them, were to be put forward 35 minutes in the earliest hours of 1 April 1892.

21. de-rgbl-1893-03-12-law Gesetz, betreffend die Einführung einer einheitlichen Zeitbestimmung. Vom 12. März 1893 (Nr. 2075), 1893-03-12, Deutsches Reich (the Emperor, with the Bundesrat and the Reichstag), Reichs-Gesetzblatt 1893, Nr. 7, ausgegeben zu Berlin den 16. März 1893 (scan from the Pomeranian Digital Library, on the Internet Archive), p. 93. Source

22. de-snn-1916-04-08-wtb Letzte Telegramme: WTB Berlin, 7. April. Amtlich (Verordnung des Bundesrats über die Sommerzeit), 1916-04-08, Straßburger Neueste Nachrichten, printing an official telegram of Wolff's Telegraphisches Bureau, Straßburger Neueste Nachrichten, 8. April 1916, Gallica view 13, col. 2. Source

    By order of the Bundesrat, every clock in the Reich went from 23:00 on 30 April 1916 to midnight, and back from 01:00 to midnight at the end of 30 September.

23. mos-matin-1918-11-21-metz L'installation de M. Mirman comme commissaire de la République en Lorraine (Metz, 19 novembre), 1918-11-21, Le Matin, Le Matin, 21 novembre 1918, p. 1, cols. 3-4 (dateline Metz, 19 novembre; the passage is in col. 4). Source

24. als-snn-1892-04-01-muenster M. E. Z., 1892-04-01, Straßburger Neueste Nachrichten, Straßburger Neueste Nachrichten, Nr. 78, Zweites Blatt, Freitag, 1. April 1892, Zweites Blatt, first page (Gallica view 5), col. 2. Source

    In the night of 31 March to 1 April 1892 the cathedral clock struck midnight and, barely a minute later, half past twelve.

25. us-star-1883-11-17-baltimore Standard Time in Baltimore, 1883-11-17, Evening Star (Washington, D.C.), Evening Star, 17 November 1883, p. 5, col. 5. Source

26. us-star-1883-11-19-bells How Father Time Was Robbed of Eight Minutes Yesterday: the fire bells to give both times, 1883-11-19, Evening Star (Washington, D.C.), Evening Star, 19 November 1883, p. 1, col. 5. Source

    Washington noon came 8 min 12 s after Eastern standard noon.

27. us-narragansett-1883-11-03-providence Local news (the railroads centering in Providence adopt standard time), 1883-11-03, Narragansett Herald (Narragansett Pier, R.I.), Narragansett Herald, 3 November 1883, p. 2, col. 1. Source

28. us-globe-1883-11-25-omaha New Standard Time: Its Adoption To-Day Throughout the Whole Northwest, 1883-11-25, Daily Globe (St. Paul, Minn.), The St. Paul Sunday Globe, 25 November 1883, p. 5, col. 3. Source

    The railway moved its clocks from Omaha time to the new central time, 23 min 40 s ahead, which is 12 min 8 s ahead of Saint Paul time. "goverened" is the paper's spelling.

29. us-globe-1883-11-25-meantime New Standard Time: Its Adoption To-Day Throughout the Whole Northwest, 1883-11-25, Daily Globe (St. Paul, Minn.), The St. Paul Sunday Globe, 25 November 1883, p. 5, col. 3. Source

30. us-pawtucket-1883-11-23-providence Local news (the new standard of time in Pawtucket and Providence), 1883-11-23, Pawtucket Gazette and Chronicle (Pawtucket, R.I.), Pawtucket Gazette and Chronicle, 23 November 1883, p. 2, col. 5. Source

    Providence adopted standard time on Tuesday 20 November 1883.

31. us-globe-1883-11-25-stpaul New Standard Time: Its Adoption To-Day Throughout the Whole Northwest, 1883-11-25, Daily Globe (St. Paul, Minn.), The St. Paul Sunday Globe, 25 November 1883, p. 5, col. 3. Source

32. us-globe-1883-11-25-minneapolis Minneapolis Globules, 1883-11-25, Daily Globe (St. Paul, Minn.), The St. Paul Sunday Globe, 25 November 1883, p. 6, col. 1. Source

33. us-indj-1883-11-19-courthouse The Change in Time: the Standard Time Duly Adopted, 1883-11-19, The Indianapolis Journal, The Indianapolis Journal, 19 November 1883, p. 8, col. 1. Source

34. us-argus-1883-11-19-chicago By Meridian Ninety: the New Standard Time Went into Effect at Noon Yesterday, 1883-11-19, The Rock Island Argus (Rock Island, Ill.), The Rock Island Argus, 19 November 1883, p. 4, col. 3. Source

35. us-star-1883-11-19-departments How Father Time Was Robbed of Eight Minutes Yesterday, 1883-11-19, Evening Star (Washington, D.C.), Evening Star, 19 November 1883, p. 1, col. 5. Source

36. us-stat-1884-dc An act to establish a standard of time in the District of Columbia (ch. 12, approved March 13, 1884), 1884-03-13, Congress of the United States (48th Congress), United States Statutes at Large, vol. 23, p. 4, 23 Stat. 4, ch. 12. Source

37. us-bourbon-1883-11-20-louisville Local notes (standard time in Louisville), 1883-11-20, Semi-Weekly Bourbon News (Paris, Ky.), Semi-Weekly Bourbon News, 20 November 1883, p. 1, col. 2. Source

Place by place

Rules and their versions

France

fr-paris-mean-time-before-1891 Paris: Paris mean time as local time, version 1

documented: Legal time was each place's local mean time (Senate, 1891); Paris's own was Paris mean time, 9 min 21 s ahead of the time adopted in 1911.

No changes before version 0.1.0.

fr-brest-lmt-before-1891 Brest: local mean time, version 3

inferred: In February 1891 the Senate heard that Brest's public clocks, all but the station's, kept local time, 27 minutes behind Paris; that they did so from 1870 is assumed.

• Version 2, 2026-09-28: Flagged inferred: the Senate debate describes Brest's clocks in February 1891 only, and the rule carries that back to 1870.
• Version 3, 2026-09-28: The window now ends at the end of 31 March, as its note says, not at the start of that day.

fr-lmt-before-1891 Local mean time of each commune, version 2

uncertain: Legal time was each place's local mean time, but the same Senate debate says towns kept some clocks to the railway station's Paris time; which one a given town's clocks showed is not recorded.

• Version 2, 2026-09-28: The window now ends at the end of 31 March, as its note says, not at the start of that day.

fr-pmt-1891 Paris mean time, legal time of France (law of 14 March 1891), version 3

documented: The law of 14 March 1891 makes Paris mean time the legal time of France.

• Version 2, 2026-09-28: The window now ends at the end of 31 March, as its note says, not at the start of that day.
• Version 3, 2026-09-28: Now the rule of the communes other than Paris; Paris has fr-paris-pmt-1891. Its end, the change of 1911, has a window to the end of March 1911 and cites a provincial report (fr-courrier-sl-1911-03-11-midnight, fr-courrier-sl-1911-03-11-chalon).

fr-paris-pmt-1891 Paris: Paris mean time as legal time (law of 14 March 1891), version 1

documented: The law of 14 March 1891 makes Paris mean time the legal time of France; Paris's clocks already showed it.

No changes before version 0.1.0.

fr-rail-interior-before-1911 Railway time inside stations: Paris mean time less five minutes, version 1

inferred: Stated for the Orléans company's lines in 1875 and for the railways generally up to 10 March 1911; assumed for the other companies and the years between.

No changes before version 0.1.0.

fr-wet-1911 Legal time: Paris mean time retarded by 9 min 21 s (law of 9 March 1911), version 2

documented: The law of 9 March 1911 fixes the offset; the post offices' order, the railways' notice and a report on Paris's public clocks fix the midnight of 10 to 11 March.

• Version 2, 2026-09-28: Now the rule of Paris's civil clocks and of the clocks inside railway stations; the other communes' civil clocks follow fr-wet-1911-provinces, whose start has a window.

fr-wet-1911-provinces Legal time outside Paris: Paris mean time retarded by 9 min 21 s (law of 9 March 1911), version 1

inferred: The law of 9 March 1911 fixes the offset. Outside Paris the post offices changed at midnight in the night of 10 to 11 March, and a Chalon-sur-Saône paper announced the new time at a bank's regulator clock for 11 March; that each commune's public clocks followed within the month is assumed.

No changes before version 0.1.0.

fr-summer-1916 Summer time 1916 (law of 9 June 1916), version 3

documented: The law and decree fix the offset and the start; the decree gives only the date of the return, and Le Petit Parisien gives the hour for all public clocks.

• Version 2, 2026-09-28: Boundary note corrected to "rather than at 23:59" (it said 23:00): Le Petit Parisien reads "au lieu de 23 heures 59".
• Version 3, 2026-09-28: Now also cites Le Petit Parisien's statement that all public clocks, the communes' among them, were to be set back at 01:00 (fr-petitparisien-1916-09-30-public-clocks).

fr-wet-1916 Normal time, winter 1916-1917, version 3

documented: Normal time restored on 1 October 1916 as the decree of 10 June 1916 provided, until the decree of 20 March 1917.

• Version 2, 2026-09-28: Boundary note corrected to "rather than at 23:59" (it said 23:00): Le Petit Parisien reads "au lieu de 23 heures 59".
• Version 3, 2026-09-28: Now also cites Le Petit Parisien's statement that all public clocks, the communes' among them, were to be set back at 01:00 (fr-petitparisien-1916-09-30-public-clocks).

fr-summer-1917 Summer time 1917 (law of 19 March 1917), version 1

documented: The law and decree fix the offset and the start; the decree gives only the date of the return, which two Paris newspapers put in the hour after midnight.

No changes before version 0.1.0.

fr-wet-1917 Normal time, winter 1917-1918, version 1

documented: Normal time restored on 7 October 1917 as the decree of 20 March 1917 provided, until the decree of 28 February 1918.

No changes before version 0.1.0.

fr-summer-1918 Summer time 1918 (decree of 28 February 1918), version 2

inferred: The decree fixes the offset and the start and gives only the date of the return. The hour, 01:00 summer time, is that of the instructions to the railway networks as Le Petit Parisien printed them; that the other public clocks were set back at the same hour is assumed.

• Version 2, 2026-09-28: Flagged inferred: the hour of the return to normal time comes from the instructions to the railway networks, and the other public clocks are assumed to have followed.

fr-wet-1918 Normal time, winter 1918-1919, version 2

inferred: Normal time was restored on 6 October 1918, as the decree of 28 February 1918 provided, until the decree of 9 February 1919. The hour of the return comes from the instructions to the railway networks; that the other public clocks followed is assumed.

• Version 2, 2026-09-28: Flagged inferred: the hour of the return to normal time comes from the instructions to the railway networks, and the other public clocks are assumed to have followed.

fr-summer-1919 Summer time 1919 (decree of 9 February 1919), version 1

documented: The decree fixes the offset and the start; it gives only the date of the return, and the Transport sub-ministry's note gives the hour.

No changes before version 0.1.0.

fr-wet-1919 Normal time from 5 October 1919, version 1

documented: Normal time restored on 5 October 1919 as the decree of 9 February 1919 provided.

No changes before version 0.1.0.

Alsace and Moselle

als-strasbourg-lmt-before-1892 Strasbourg: local mean time, version 3

inferred: The 1892 change (the cathedral clock struck midnight and, a minute later, half past twelve) fits Strasbourg mean time; that the city's clocks kept it from 1870, through the siege of 1870 and the annexation of 1871, is assumed.

• Version 2, 2026-09-28: Flagged inferred again: the sources show Strasbourg mean time only at the change of 1892, and the rule carries it back to 1870 across the siege and the annexation. The change is timed by the cathedral clock only; the other public clocks were corrected during 1 April, now a window.
• Version 3, 2026-09-28: The window of the change now opens at noon on 31 March: the tower clocks of the suburb of Ruprechtsau already showed Mid-European time that afternoon (als-snn-1892-04-01-ruprechtsau).

mos-metz-lmt-before-1892 Metz: local mean time, version 2

inferred: The city's clocks were put forward 35 minutes to Mid-European time in 1892, which fits Metz mean time; that they kept it from 1870, through the siege of 1870 and the annexation of 1871, is assumed.

• Version 2, 2026-09-28: Flagged inferred again: the sources show Metz mean time only at the change of 1892, and the rule carries it back to 1870 across the siege and the annexation.

als-strasbourg-mez-1892 Strasbourg: Mid-European time as local time (order of the Ministry for Alsace-Lorraine, 1892), version 3

documented: The Ministry ordered Mid-European time as local time throughout Alsace-Lorraine from 1 April 1892; the cathedral clock changed at midnight, and the tower clocks of Ruprechtsau the afternoon before.

• Version 2, 2026-09-28: The start is timed by the cathedral clock only; the other public clocks were corrected during 1 April, now a window.
• Version 3, 2026-09-28: The window of the change now opens at noon on 31 March: the tower clocks of the suburb of Ruprechtsau already showed Mid-European time that afternoon (als-snn-1892-04-01-ruprechtsau).

mos-metz-mez-1892 Metz: Mid-European time as local time (order of the Ministry for Alsace-Lorraine, 1892), version 1

documented: The Ministry ordered Mid-European time as local time throughout Alsace-Lorraine from 1 April 1892; the city's clocks were to be put forward in the earliest hours of that day.

No changes before version 0.1.0.

de-mez-1893 Mid-European time, legal time of Germany (law of 12 March 1893), version 1

documented: The law of 12 March 1893 makes the mean time of the 15th meridian east the legal time of Germany from 1 April 1893.

No changes before version 0.1.0.

de-summer-1916 German summer time 1916 (Bundesrat order of 6 April 1916), version 1

documented: The official telegram on the Bundesrat order gives the offset and both changes for every clock in the Reich.

No changes before version 0.1.0.

de-mez-1916 Mid-European time, winter 1916-1917, version 1

documented: Legal time under the law of 1893 between the summer times of 1916 and 1917.

No changes before version 0.1.0.

de-summer-1917 German summer time 1917, version 1

documented: A Strasbourg newspaper reports clocks put forward at 02:00 on Monday 16 April 1917 and announces the return at 03:00 on 17 September.

No changes before version 0.1.0.

de-mez-1917 Mid-European time, winter 1917-1918, version 1

documented: Legal time under the law of 1893 between the summer times of 1917 and 1918.

No changes before version 0.1.0.

de-summer-1918 German summer time 1918, version 1

documented: A Strasbourg newspaper gives the public clocks forward at 02:00 on 15 April and back at 03:00 on 16 September 1918.

No changes before version 0.1.0.

als-strasbourg-mez-1918 Strasbourg: Mid-European time, autumn 1918, version 1

documented: Legal time under the law of 1893 until the mayor's notice put the public clocks on French time at noon on 21 November 1918.

No changes before version 0.1.0.

mos-metz-mez-1918 Metz: Mid-European time, autumn 1918, version 1

documented: Legal time under the law of 1893 until the cathedral clock was put on French time on the morning of 19 November 1918.

No changes before version 0.1.0.

als-strasbourg-french-1918 Strasbourg: 'French time' as the city set it, five minutes ahead of Greenwich, version 2

uncertain: The city set its clocks to 11:05 at noon Mid-European time, five minutes ahead of Greenwich and of French legal time, and they were still so in mid-December; when they were corrected is not known.

• Version 2, 2026-09-28: The end note states the decision: the five minutes end at the latest date the sources allow, the start of summer time, and are not carried into summer time as +1:05.

mos-metz-french-1918 Metz: French time from 19 November 1918, version 2

uncertain: A report has the cathedral clock on French time from the morning of 19 November 1918 without saying by how much it changed; the atlas takes French legal time (+0:00), but when Strasbourg went over to French time two days later, the city set its clocks five minutes ahead of Greenwich.

• Version 2, 2026-09-28: Flagged uncertain: the size of the change is not reported, and Strasbourg's clocks, put on French time two days later, were five minutes ahead of Greenwich.

als-mos-summer-1919 French summer time 1919 in Alsace and Lorraine, version 2

uncertain: The railways of Alsace and Lorraine put their clocks forward to French summer time at 23:00 on 1 March 1919; the atlas takes the cities' public clocks to have gone to it too (+1:00), though Strasbourg's had been five minutes fast that winter and could have become +1:05.

• Version 2, 2026-09-28: Flagged uncertain: whether the cities' public clocks went to French summer time (+1:00) or kept a five-minute difference (+1:05) is not known.

als-mos-wet-1919 French legal time from 5 October 1919 in Alsace and Lorraine, version 1

inferred: Assumed to follow the return to normal time in the rest of France on 5 October 1919; no Alsatian or Lorraine source was found for it.

No changes before version 0.1.0.

The United States

us-eastern-dst-1918 Eastern daylight saving time 1918 (Standard Time Act, 1918), version 2

inferred: The Act of 19 March 1918 advances each zone's standard time one hour from 02:00 on the last Sunday in March to 02:00 on the last Sunday in October. The Interstate Commerce Commission's zone order was not read: a report says that for 1918 it recognized the zone limits already in use, and each covered city is taken to be in the zone whose time it had kept since 1883 or 1884.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone order was not read, so which zone each city was in is assumed from the time it had kept since 1883 or 1884. A report that the Commission recognized the existing zone limits for 1918 is now cited.

us-eastern-1918 Eastern standard time, winter 1918-1919, version 2

inferred: Standard time of the zone under the Act of 19 March 1918 between its first and second summers; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-eastern-dst-1919 Eastern daylight saving time 1919, version 2

inferred: The Act again advanced the clocks on the last Sunday in March 1919, and the repeal of August 1919 took effect after the last Sunday in October; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-eastern-1919 Eastern standard time from 26 October 1919, version 2

inferred: The repeal returned each zone to the mean time of its meridian on the last Sunday in October 1919; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-central-dst-1918 Central daylight saving time 1918 (Standard Time Act, 1918), version 2

inferred: The Act of 19 March 1918 advances each zone's standard time one hour from 02:00 on the last Sunday in March to 02:00 on the last Sunday in October. The Interstate Commerce Commission's zone order was not read: a report says that for 1918 it recognized the zone limits already in use, and each covered city is taken to be in the zone whose time it had kept since 1883 or 1884.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone order was not read, so which zone each city was in is assumed from the time it had kept since 1883 or 1884. A report that the Commission recognized the existing zone limits for 1918 is now cited.

us-central-1918 Central standard time, winter 1918-1919, version 2

inferred: Standard time of the zone under the Act of 19 March 1918 between its first and second summers; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-central-dst-1919 Central daylight saving time 1919, version 2

inferred: The Act again advanced the clocks on the last Sunday in March 1919, and the repeal of August 1919 took effect after the last Sunday in October; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-central-1919 Central standard time from 26 October 1919, version 2

inferred: The repeal returned each zone to the mean time of its meridian on the last Sunday in October 1919; which zone each city was in is assumed, as for 1918.

• Version 2, 2026-09-28: Flagged inferred: the Interstate Commerce Commission's zone orders were not read, so which zone each city was in is assumed.

us-nyc-city-time-before-1883 New York: New York city time, version 2

inferred: The City Hall clock was stopped for "Three minutes 58 seconds and 38-100 seconds" to take up Eastern time, so city time was 4 h 56 min 1.62 s behind Greenwich (the longitude gives 4 h 56 min 1.4 s); that the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: Flagged inferred: the report describes the city's time at the change of 1883 only, and the rule carries it back to 1870.

us-nyc-eastern-1883 New York: Eastern standard time, version 1

documented: The mayor signed the resolution that from noon on 18 November 1883 all time in the city conform to the 75th-meridian standard.

No changes before version 0.1.0.

us-baltimore-city-time-before-1883 Baltimore: Baltimore city time, version 2

inferred: The new standard "advances Baltimore time six minutes and twenty-eight seconds", so city time was 5 h 6 min 28 s behind Greenwich (the longitude gives 5 h 6 min 26.9 s); that the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: Flagged inferred: the report describes the city's time at the change of 1883 only, and the rule carries it back to 1870.

us-baltimore-eastern-1883 Baltimore: Eastern standard time, version 1

documented: The new standard was announced to take effect at noon on 18 November 1883, with city time reckoned by it.

No changes before version 0.1.0.

us-washington-city-time-before-1883 Washington: Washington mean time, version 2

inferred: The Naval Observatory was to signal the new time "eight minutes and twelve seconds earlier" than Washington noon, so Washington time was 5 h 8 min 12 s behind Greenwich (the longitude gives 5 h 8 min 8.7 s); that the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: Flagged inferred: the report describes the city's time at the change of 1883 only, and the rule carries it back to 1870.

us-washington-two-times-1883 Washington: Washington mean time kept officially while standard time spread, version 2

uncertain: From 18 November 1883 the railroads and the businesses dealing with them kept Eastern time, while other businesses, the government departments and the fire bells at noon kept Washington time until Congress acted; the atlas gives Washington time.

• Version 2, 2026-09-28: The window now ends at the end of 31 March, as its note says, not at the start of that day.

us-washington-eastern-1884 Washington: Eastern standard time, version 2

documented: The act of 13 March 1884 makes the mean time of the 75th meridian the legal standard of time in the District of Columbia.

• Version 2, 2026-09-28: The window now ends at the end of 31 March, as its note says, not at the start of that day.

us-providence-city-time-before-1883 Providence: Providence time (local mean time), version 2

inferred: The railroads centering in Providence were to make "a set back of 14 minutes and 40 seconds", so that "the railroad time will be fifteen minutes slower than Providence time". Taking the set-back as measured from Providence time, the atlas puts Providence time 4 h 45 min 20 s behind Greenwich (the report rounds it to fifteen minutes; the longitude gives 4 h 45 min 39.1 s) and assumes the city kept it from 1870.

• Version 2, 2026-09-28: City time now taken from the report ("a set back of 14 minutes and 40 seconds"), as for every city whose change a report measures, instead of from the longitude; reason corrected.

us-providence-eastern-1883 Providence: Eastern standard time, version 1

documented: The city authorities adopted the new time on Tuesday 20 November 1883.

No changes before version 0.1.0.

us-indianapolis-city-time-before-1883 Indianapolis: Indianapolis local time (local mean time), version 3

inferred: "Yesterday afternoon the court-house clock was set back sixteen minutes", so city time is taken as 5 h 44 min behind Greenwich, 16 minutes ahead of Central time (the report gives whole minutes; the longitude gives 5 h 44 min 37.9 s); that the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: City time now taken from the report ("set back sixteen minutes"), as for every city whose change a report measures, instead of from the longitude; the reason no longer mentions fifteen minutes, which no cited source says.
• Version 3, 2026-09-28: The window of the change now opens at noon by the old city time (11:44 Central): the report does not say whether the change came at noon by the old time or the new.

us-indianapolis-central-1883 Indianapolis: Central standard time, version 2

documented: Central standard time went into effect at noon on 18 November 1883 and the court-house clock was set back the same afternoon.

• Version 2, 2026-09-28: The window of the change now opens at noon by the old city time (11:44 Central): the report does not say whether the change came at noon by the old time or the new.

us-louisville-city-time-before-1883 Louisville: Louisville city time, version 2

uncertain: A Paris, Ky., paper reports that "the city clock was turned back 18 minutes", which puts city time at -5:42:00; the mean time of the city's longitude, -5:43:02.3, is 62 s behind that, and the 18 minutes may describe the railroad's change rather than the city clock's. The atlas uses the report.

• Version 2, 2026-09-28: Flagged uncertain: the 18 minutes come from one second-hand sentence and differ from the longitude by 62 seconds; both readings are given. The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set.

us-louisville-central-1883 Louisville: Central standard time, version 2

documented: The fire bells rang noon by Central time on 18 November 1883 and the city clock was set back to it.

• Version 2, 2026-09-28: The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set.

us-chicago-city-time-before-1883 Chicago: Chicago time (local mean time), version 2

inferred: The new central time "is nine minutes slower than Chicago time", so Chicago time is taken as 5 h 51 min behind Greenwich (the report gives whole minutes; the longitude gives 5 h 50 min 36 s); that the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: City time now taken from the report ("nine minutes slower than Chicago time"), as for every city whose change a report measures, instead of from the longitude; flagged inferred, the report describing the city's time at the change only. The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set.

us-chicago-central-1883 Chicago: Central standard time, version 2

inferred: Standard time was inaugurated in Chicago at noon on 18 November 1883 and adopted by the railroads, the Board of Trade, hotels and businesses; action by the city government is not reported, and the public clocks are assumed to have followed.

• Version 2, 2026-09-28: The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set. Flagged inferred: the city government's own action is not reported.

us-saint-paul-city-time-before-1883 Saint Paul: Saint Paul mean time, version 2

inferred: The new time was "twelve minutes faster than the old time", and a railroad's change was "ahead 12 minutes and 8 seconds by St. Paul time"; the atlas takes Saint Paul time as 6 h 12 min 8 s behind Greenwich (the longitude gives 6 h 12 min 22.4 s) and assumes the city kept it from 1870.

• Version 2, 2026-09-28: City time now taken from the report ("ahead 12 minutes and 8 seconds by St. Paul time"), as for every city whose change a report measures, instead of from the longitude; flagged inferred, the report describing the city's time at the change only. The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set.

us-saint-paul-central-1883 Saint Paul: Central standard time, version 2

documented: Standard time was inaugurated at noon on 25 November 1883, and the city council and chamber of commerce adopted it.

• Version 2, 2026-09-28: The adoption instant now has a window: the source does not say whether the change was at noon by the old time or the new, or when that day the clocks were set.

us-minneapolis-city-time-before-1883 Minneapolis: Minneapolis local time (local mean time), version 2

inferred: No report gives Minneapolis's own figure, so the mean time of the city's longitude is used, 13 min 3.3 s behind Central time; neighbouring Saint Paul called its old time its "former meantime". That the city kept it from 1870 is assumed.

• Version 2, 2026-09-28: Reason corrected: Saint Paul's time now comes from a report, so Minneapolis, which no report measures, is no longer said to follow it.

us-minneapolis-central-1883 Minneapolis: Central standard time, version 2

inferred: Standard time was to be "generally adopted in Minneapolis" on 25 November 1883, and two days later it was "working finely throughout Minneapolis", though "some are slow in adopting it"; action by the city government is not reported, and the public clocks are assumed to have followed.

• Version 2, 2026-09-28: Flagged inferred, as Chicago's adoption is: the reports describe general use, not the city government's action. A report of 27 November, after the change, is now cited (us-globe-1883-11-27-minneapolis).

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