tzdata rule group
Denver
Historical rule context · 1 represented zone
A rule group describes recurring clock changes. It is not itself a place or an IANA time-zone identifier.
- First rule
- 1920
- Last rule
- 1966
- Rule entries
- 5
- Source files
- northamerica
Notes from the time database
Context for this rule
These source notes are preserved from tzdata. They help explain a rule’s period, without adding claims beyond the source.
US mountain time, represented by Denver Colorado, far western Kansas, Montana, western Nebraska, Nevada border (Jackpot, Owyhee, and Mountain City), New Mexico, southwestern North Dakota, western South Dakota, far western Texas (El Paso County, Hudspeth County, and Pine Springs and Nickel Creek in Culberson County), Utah, Wyoming On 1921-03-04 federal law placed all of Texas into the central time zone. However, El Paso ignored the law for decades and continued to observe mountain time, on the grounds that that's what they had always done and they weren't about to let the federal government tell them what to do. Eventually the federal government gave in and changed the law on 1970-04-10 to match what El Paso was actually doing. Although that's slightly after our 1970 cutoff, there is no need to create a separate zone for El Paso since they were ignoring the law anyway. See: Long T. El Pasoans were time rebels, fought to stay in Mountain zone. El Paso Times. 2018-10-24 06:40 -06.
Where it appears
Zones using Denver
Only historically distinct canonical zones from this atlas are listed.
United States of AmericaOriginal rule fields
Recorded rule entries
Structured directly from tzdata’s Rule lines.
| From | To | Type | In | On | At | Save |
|---|---|---|---|---|---|---|
| 1920 | 1921 | - | Mar | lastSun | 2:00 | 1:00 |
| 1920 | only | - | Oct | lastSun | 2:00 | 0 |
| 1921 | only | - | May | 22 | 2:00 | 0 |
| 1965 | 1966 | - | Apr | lastSun | 2:00 | 1:00 |
| 1965 | 1966 | - | Oct | lastSun | 2:00 | 0 |