Historically distinct IANA time zone
America/Phoenix
- Countries
- United States of America
- GPS reference
- 33.45° N, 112.07° W
- Data source
- IANA northamerica
- Aliases
- MST, US/Arizona
- Rule groups
- US
United States of AmericaMST - AZ (except Navajo)
Geographic context
Where this clock belongs
The map marks the IANA reference location and associated country, not a time-zone boundary.
GPS reference: 33.45° N, 112.07° W. Associated countries: US.
The Wikipedia link provides additional context; it is not evidence for a historical claim. Transition data comes from the IANA source file.
Notes from the time database
The story behind the clock
These source notes describe a period or rule. They do not, by themselves, establish a causal claim for a particular clock change.
War
Peace
Original IANA source file: northamerica.
A shared present
Same clock today, different past
These nearby zones follow the same current annual pattern, yet retain their own historical record.
Mexico · 498 km from the reference location · Same annual clock since 1999
Canada · 2560 km from the reference location · Same annual clock since 1973Civil-time record
Recorded changes over time
From 1883 to 1967 · 11 recorded transitions
Recurring daylight-saving changes are grouped separately when JavaScript is available.
Notable changes
One-off changes and transitions outside the recurring seasonal rhythm.
- -07:00 · MSTStandard time applies
- -06:00 · MDTDaylight saving time begins
- -07:00 · MSTStandard time applies
- -06:00 · MDTDaylight saving time begins
- -07:00 · MSTStandard time applies
- -06:00 · MWTDaylight saving time begins
Browse every recorded transition
| Local time after transition | Offset after | Abbreviation | Rule |
|---|---|---|---|
| 1883-11-18 12:00 | -07:00 | MST | Standard time |
| 1918-03-31 03:00 | -06:00 | MDT | Daylight saving time |
| 1918-10-27 01:00 | -07:00 | MST | Standard time |
| 1919-03-30 03:00 | -06:00 | MDT | Daylight saving time |
| 1919-10-26 01:00 | -07:00 | MST | Standard time |
| 1942-02-09 03:00 | -06:00 | MWT | Daylight saving time |
| 1943-12-31 23:01 | -07:00 | MST | Standard time |
| 1944-04-01 01:01 | -06:00 | MWT | Daylight saving time |
| 1944-09-30 23:01 | -07:00 | MST | Standard time |
| 1967-04-30 03:00 | -06:00 | MDT | Daylight saving time |
| 1967-10-29 01:00 | -07:00 | MST | Standard time |