Time Zone History

Hermosillo time zone history

Hermosillo kept local mean time (UTC−7:23:52) until 1921, tied for the latest switch among the 11 zones on UTC−7 standard time with local mean time in the record. Daylight saving time was used in 3 years since 1970, last in 1998; under the current rules the clocks no longer change.

UTC−7

Standard time is UTC−7 (MST) all year under the current rules.

Covers: Sonora · tz database name America/Hermosillo

Convert a time from Hermosillo

Summer time in 3 of 57 years since 1970

UTC−7:23:52: 24 minutes behind today’s standard timeUTC−7: today’s standard timeUTC−6: 1 hour ahead of today’s standard timeUTC−7:23:52: 24 minutes behindtoday’s standard timeUTC−7: today’s standard timeUTC−6: 1 hour ahead of today’sstandard time

How to read this chart

Before 1970

19101920193019401950196019701910192019301940195019601970
JanFebMarAprMayJunJulAugSepOctNovDec1970198019902000201020202028JFMAMJJASOND1970198019902000201020202028

Standard time changes

DateChangeNew standard timeClock label
Before 1970
December 31, 1921Local mean time (UTC−7:23:52) replacedUTC−7MST
June 10, 1927Standard time forward 1 hourUTC−6CST
November 15, 1930Standard time back 1 hourUTC−7MST
April 1, 1932Standard time forward 1 hourUTC−6CST
April 24, 1942Standard time back 1 hourUTC−7MST

Daylight saving periods

YearsClocks go forwardClocks go backShift and labels
Before 1970
1931April 30October 11 hour, MST to MDT
Since 1970
1996–1998first Sunday in April, 02:00last Sunday in October, 02:001 hour, MST to MDT

Also on UTC−7

Phoenix (United States), Ciudad Juárez (Mexico), Mazatlan (Mexico), Denver (United States), Boise (United States), Vancouver (Canada), Dawson Creek (Canada), Fort Nelson (Canada), Whitehorse (Canada) and Dawson (Canada) (nearest first; 1 more on the list of offsets).

Clocks next door since 1970

  • Chihuahua (478 km): usually 1 hour ahead; different on 4,061 days in 1996–2022.
  • Phoenix (United States) (498 km): same time except 609 days in 1996–1998.
  • Ciudad Juárez (522 km): usually 1 hour ahead; different on 4,210 days in 1996–2026; same time today.
  • Ojinaga (637 km): usually 1 hour ahead; different on 4,621 days in 1996–2026.
  • Tijuana (694 km): same time except 9,320 days in 1970–2026; 1 hour behind today.

How it compares

Standard time has stayed at UTC−7 since 1942.

On standard time, clocks in Hermosillo run 24 minutes ahead of local mean solar time.