> "US Mountain Standard Time" (used by Outlook) is the same as "US/Arizona" (used by PHP among others).
It's not quite that simple. During Daylight Saving Time, Arizona stays on US Mountain Standard Time; i.e., it's the same as Pacific Daylight Time and one hour behind Mountain Daylight Time. During the rest of the year, Arizona is on the same time as the rest of Mountain Standard Time, or one hour ahead of Pacific Time.
It's not quite that simple. During Daylight Saving Time, Arizona stays on US Mountain Standard Time; i.e., it's the same as Pacific Daylight Time and one hour behind Mountain Daylight Time. During the rest of the year, Arizona is on the same time as the rest of Mountain Standard Time, or one hour ahead of Pacific Time.