Arizona does not observe Daylight Saving Time (early/mid-March through early November). We do not "spring forward" in Phoenix — we always stay on the same time zone. During Daylight Saving Time (DST) most of Arizona is at the same time as California (Pacific Daylight Time or PDT). That doesn't mean that we switch to their time zone; it simply means that during half the year our time zones happen to be at the same time relative to UTC.
Arizona's Time Zone
The Arizona time zone is the Mountain Standard Time (MST) zone. Other states included in this time zone are Colorado, Montana, New Mexico, Utah, and Wyoming. Parts of the following states also use MST: Idaho, Kansas, Nebraska, North Dakota, Oregon, South Dakota, Texas.
The Mountain Standard Time zone is 7 hours behind UTC (Universal Time, Coordinated). I explain what that means, and how to tell what time it is in Arizona right now.
On the first Sunday in November, when DST ends, most everyone else in the country "falls back" or sets their clock back one hour. In Phoenix we do not. From that first Sunday in November through the second Sunday in March we are one hour ahead of those states on Pacific Standard Time, like California and Nevada; one hour behind states in the Central Time zone, such as Texas and Illinois; and only two hours behind those states on Eastern Time, such as New York and Florida.
The only exception in Arizona is the Navajo Nation, in northeastern Arizona, which does observe Daylight Saving Time.
Is Arizona Breaking the Law?
You might ask, isn't the changing of the clocks a federal law? The answer is that although Daylight Saving Time was established by federal law in 1966, a state or area may choose not to observe it.
If a state chooses to observe it, however, it must always observe it at the same time as the other states in the U.S.
Other areas in the U.S. that don't observe Daylight Saving Time are Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands. In Arizona, we just don't need another hour of sunlight! Read the history and see a time line about Arizona's relationship with Daylight Saving Time.
Final Tip, and a Pet Peeve of Mine!
It is NOT Daylight Savings time--there's no "s" after Saving. It's Daylight Saving Time, singular.