Is Las Vegas always an hour behind Phoenix?

No. The two cities share the same clock for roughly half the year. From the second Sunday of March to the first Sunday of November, Las Vegas and Phoenix both sit at UTC−7. The rest of the year, Las Vegas falls back to UTC−8 and Phoenix stays put. That one-hour gap catches more people than any other quirk on the Nevada, Arizona line.

The reason is simple. Nevada observes Daylight Saving Time. Arizona does not.

In summer, Las Vegas runs on Pacific Daylight Time (PDT, UTC−7). Phoenix runs on Mountain Standard Time (MST, UTC−7). The offsets match. In winter, Las Vegas switches to Pacific Standard Time (PST, UTC−8) while Phoenix remains on MST. Las Vegas is one hour behind.

A concrete example: In January, noon in Las Vegas is 1:00 PM in Phoenix. In July, noon is noon in both cities.

Why does Phoenix skip daylight saving when Las Vegas doesn’t?

The Uniform Time Act of 1966 let states exempt themselves from DST. Arizona took the opt-out and never looked back. The deciding factor was summer heat. Pushing an extra hour of daylight into the evening means pushing peak temperatures later. In a state where summer routinely tops 38°C, that is not a selling point. The legislature chose year-round standard time instead.

There is one carve-out: the Navajo Nation, which extends into northeastern Arizona, does observe DST. But Phoenix, Tucson, Flagstaff, and the rest of the state keep their clocks fixed.

Nevada made the opposite choice. Las Vegas follows the same DST schedule as California: spring forward on the second Sunday of March, fall back on the first Sunday of November.

When do Las Vegas and Phoenix share the same clock?

Here are the exact transition dates from the IANA time zone database.

2026 - Las Vegas springs forward: Sunday, 8 March, 02:00 local → 03:00 (PDT, UTC−7). From this moment, Las Vegas and Phoenix show the same time. - Las Vegas falls back: Sunday, 1 November, 02:00 local → 01:00 (PST, UTC−8). From this moment, Phoenix is one hour ahead.

2027 - Las Vegas springs forward: Sunday, 14 March, 02:00 local → 03:00 (PDT). Clocks match again. - Las Vegas falls back: Sunday, 7 November, 02:00 local → 01:00 (PST). Phoenix pulls ahead by one hour.

During the matching stretch, a call between the two cities needs no conversion. During the divergent stretch, add one hour when dialling from Las Vegas to Phoenix. Subtract one hour going the other way.

What the time border means for travel, calls, and live events

Road trips

Driving from Las Vegas to Phoenix crosses the state line but not a traditional time zone boundary. In summer, both cities sit at UTC−7. No clock change at the border. In winter, you gain one hour entering Arizona.

Driving from Las Vegas to Denver works differently. Denver observes Mountain Time with DST, so the gap is one hour year-round (Denver ahead), except during the brief spring and autumn transition windows.

Business calls and meetings

Schedule a January meeting between Las Vegas and Phoenix and you must account for the gap. A 10:00 AM start in Las Vegas is 11:00 AM in Phoenix. In July, 10:00 AM is 10:00 AM in both cities.

For multi-zone conference calls, Las Vegas’s best window with the East Coast (11:00 AM to 2:00 PM Pacific) shifts relative to Phoenix in winter but not in summer.

Broadcast and live events

Las Vegas shows and sports are timed for East Coast prime time. A 5:00 PM Pacific start in Las Vegas hits 8:00 PM Eastern. In winter, that same 5:00 PM start is 6:00 PM in Phoenix. In summer, it is 5:00 PM in both. The scheduling logic is simple: capture the largest U.S. television audience.

What stays constant

A few relationships never change with the season.

Las Vegas is always 3 hours behind New York. Both cities observe DST and shift on the same dates. Las Vegas is always 8 hours behind London. The offset holds steady because the UK and Las Vegas adjust clocks on similar schedules. Solar noon in Las Vegas shifts with DST but has no connection to Arizona.

Quick reference: Las Vegas vs Phoenix

When Las Vegas time Phoenix time Difference
Summer (March, November) PDT (UTC−7) MST (UTC−7) Same time
Winter (November, March) PST (UTC−8) MST (UTC−7) Phoenix 1 hour ahead

Checklist:

  • [ ] Between the second Sunday of March and the first Sunday of November? Same time.
  • [ ] Between the first Sunday of November and the second Sunday of March? Phoenix is one hour ahead.
  • [ ] When in doubt, use UTC. Las Vegas is UTC−8 in winter, UTC−7 in summer. Phoenix is always UTC−7.