Time Zone History

Dominican Republic time zone history

Its seasonal clock changes since 1970 include moves of 30 minutes, not the usual hour. The Dominican Republic has changed its standard time 3 times since 1970, the most of the 19 zones on UTC−4 standard time. On standard time, clocks at Santo Domingo run 40 minutes ahead of local mean solar time, the second-largest gap of the 14 zones on UTC−4 standard time whose clocks run ahead of the sun.

UTC−4

Standard time is UTC−4 (AST) all year under the current rules.

tz database name America/Santo_Domingo

Convert a time from Dominican Republic

Summer time in 5 of 57 years since 1970

UTC−5: 1 hour behind today’s standard timeUTC−4:40, UTC−4:39:36, UTC−4:30: behind today’s standard timeUTC−4: today’s standard timeUTC−5: 1 hour behind today’sstandard timeUTC−4:40, UTC−4:39:36, UTC−4:30:behind today’s standard timeUTC−4: today’s standard time

How to read this chart

Before 1970

18801900192019401960188019201960
JanFebMarAprMayJunJulAugSepOctNovDec1970198019902000201020202028JFMAMJJASOND1970198019902000201020202028

Standard time changes

DateChangeNew standard timeClock label
Before 1970
January 1, 1890Local mean time (UTC−4:39:36) replacedUTC−4:40SDMT
April 1, 1933Standard time back 20 minutesUTC−5EST
Since 1970
October 27, 1974Standard time forward 1 hourUTC−4AST
October 29, 2000Standard time back 1 hourUTC−5EST
December 3, 2000Standard time forward 1 hourUTC−4AST

Daylight saving periods

YearsClocks go forwardClocks go backShift and labels
Before 1970
1966October 30not that year1 hour, EST to EDT
1967not that yearFebruary 281 hour, EST to EDT
1969October 26not that year30 minutes
Since 1970
1970October 25February 2130 minutes
1971October 31January 2030 minutes
1972–1973last Sunday in October, 00:0021 January, 00:0030 minutes
1974not that yearJanuary 2130 minutes

Also on UTC−4

Puerto Rico, Venezuela, Martinique, Barbados, Bermuda, Guyana, Boa Vista (Brazil), Manaus (Brazil), Halifax (Canada) and Porto Velho (Brazil) (nearest first; 8 more on the list of offsets).

Clocks next door since 1970

  • Haiti (257 km): usually 1 hour behind; different on 8,521 days in 37 different years between 1970 and 2026.
  • Turks and Caicos Islands (358 km): same time except 8,656 days in 1970–2015 and 2018–2026; 1 hour behind today.
  • Puerto Rico (400 km): same time except 1,795 days in 1970–1974 and 2000.
  • Jamaica (730 km): usually 1 hour behind; different on 3,524 days in 1970–1983 and 2000.
  • Venezuela (942 km): same time except 4,861 days in 1970–1974, 2000 and 2007–2016.

How it compares

The record holds 5 different UTC offsets, the second-most of the 19 zones on UTC−4 standard time.

Daylight saving time was used in 5 years since 1970, last in 1974; under the current rules the clocks no longer change.