Pacific Daylight Time

The Pacific Time Zone observes standard time by subtracting eight hours from Coordinated Universal Time (UTC−8). The standard time in this zone is based on the mean solar time of the 120th meridian west of the Greenwich Observatory. During daylight saving time, its time offset is UTC−7 and is thus based on the mean solar time of the 105th meridian west of the Greenwich Observatory.

In the United States and Canada, this time zone is generically called the Pacific Time Zone (PT). Specifically, it uses Pacific Standard Time (PST) when observing standard time (late autumn to early spring), and Pacific Daylight Time (PDT) when observing daylight saving time (early spring to late autumn). Most of Canada uses daylight saving time. In Mexico the UTC−8 time zone is known as the Northwest Zone, which is synchronized with the U.S. PDT daylight saving schedule.

The largest city in the Pacific Time Zone is Los Angeles in California from USA; the city's metropolitan area is the largest in the zone.

The zone is one hour ahead of the Alaska Time Zone, one hour behind the Mountain Time Zone, two hours behind the Central Time Zone, and three hours behind the Eastern Time Zone.