The 1-hour gap explained
When it’s noon in Los Angeles, it’s 13:00 in Denver. That one-hour gap holds all year for most of the Mountain Time zone.
The reason: Pacific Time (UTC−8 winter, UTC−7 summer) and Mountain Time (UTC−7 winter, UTC−6 summer) both observe daylight saving on the same schedule. They shift together. The gap stays constant.
The common mistake: assuming the difference changes with daylight saving. It doesn’t. Both zones spring forward and fall back on the same dates, so the 1-hour offset is permanent for most locations.
What’s the conversion from Pacific Time to Mountain Time?
| If you have this time in Pacific | Your Mountain Time is |
|---|---|
| 6:00 AM PST / PDT | 7:00 AM MST / MDT |
| 9:00 AM PST / PDT | 10:00 AM MST / MDT |
| 12:00 PM PST / PDT | 1:00 PM MST / MDT |
| 3:00 PM PST / PDT | 4:00 PM MST / MDT |
| 6:00 PM PST / PDT | 7:00 PM MST / MDT |
| 9:00 PM PST / PDT | 10:00 PM MST / MDT |
| 12:00 AM PST / PDT | 1:00 AM MST / MDT |
The conversion is always +1 hour. No exceptions for most cities.
Why does Phoenix sometimes show the same time as Los Angeles?
The state does not observe daylight saving time. It stays on Mountain Standard Time (MST, UTC−7) year-round.
Here’s where it gets confusing:
- Winter (November, March): The state is on MST (UTC−7). Pacific is on PST (UTC−8). Pacific is 1 hour behind. Normal.
- Summer (March, November): The state stays on MST (UTC−7). Pacific switches to PDT (UTC−7). They match. Both are UTC−7.
So in summer, Phoenix and Los Angeles show the same clock time. This creates the “same time as California” confusion. People assume Phoenix is on Pacific Time. It isn’t. The state is Mountain Time, but without DST it drifts into sync with Pacific during daylight saving months.
The rule: it’s always Mountain Time. It just happens to align with Pacific in summer because it refuses to spring forward.
Quick-reference conversion table
| Season | Pacific offset | Mountain offset (most areas) | Arizona offset | Difference (Pacific → Arizona) |
|---|---|---|---|---|
| Winter (PST) | UTC−8 | UTC−7 (MST) | UTC−7 (MST) | +1 hour |
| Summer (PDT) | UTC−7 | UTC−6 (MDT) | UTC−7 (MST) | 0 hours (same time) |
How do I schedule a call from Las Vegas to Denver or LA to Phoenix?
Las Vegas (Pacific) to Denver (Mountain): - Las Vegas is on Pacific Time (America/Los_Angeles). Denver is on Mountain Time (America/Denver). - 12:00 PM in Las Vegas → 1:00 PM in Denver. Always. - Denver observes DST, so the gap never changes.
Los Angeles (Pacific) to Phoenix (Mountain, no DST): - Los Angeles is on Pacific Time. Phoenix is on Mountain Time but skips DST. - In January (PST): 12:00 PM LA → 1:00 PM Phoenix. Normal. - In July (PDT): 12:00 PM LA → 12:00 PM Phoenix. Same clock. Confusing, but correct.
What to do: When scheduling between Pacific and Phoenix in summer, verify the date. If DST is in effect, no conversion needed. If DST is not in effect, add 1 hour.
Quick checklist for Pacific to Mountain conversions
- Is the Mountain location in the state that skips DST? If yes, check the date. Summer = same time. Winter = +1 hour.
- Is the Mountain location anywhere else (Denver, Salt Lake City, Albuquerque)? Add 1 hour. Always.
- Are you looking at PST or PDT? Doesn’t matter for the conversion. The +1 hour rule works for both, except for that one state in summer.