PST to MST

Arizona has not observed daylight saving since 1968 because extra evening sunlight is the last thing a desert city needs in July. It stays on UTC−7 year-round. California moves from UTC−8 to UTC−7 in March, which brings Los Angeles level with Phoenix until the first Sunday of November. For drivers on Interstate 10 between the two, the clock only changes at the state line in winter.

Many Californians live or work across this line: Las Vegas (Pacific) to Phoenix (Mountain, no DST) is a common business route, and the Phoenix area attracts remote workers whose teams are in California. In summer they can treat both cities as one time zone; from November to March they need the one-hour shift.

The Pacific–Mountain line cuts through two states. Idaho's northern panhandle, including Coeur d'Alene and Lewiston, is on Pacific Time, while Boise and the south are on Mountain Time. In Oregon, most of Malheur County near the Idaho border follows Mountain Time. Colorado, Utah, Wyoming, New Mexico and Montana are entirely Mountain.

A flight from Los Angeles to Denver takes about two and a half hours, so leaving at 10:00 AM puts you on the ground around 1:30 PM Mountain. For conversions across the whole country, the time zone converter compares any two US zones.