Although often referred to as Daylight Savings Time (with an 's' on Saving) the true designation is Daylight Saving Time (DST).
The state of Arizona is on Mountain Standard Time but, with the exception of the Navajo Nation, does not observe Daylight Saving Time. When Daylight Saving Time takes effect for the rest of the country in the spring, most of the state of Arizona does not set clocks ahead.
Arizona State Library, Archives & Public Records provides additional information.
Arizona, including Tucson, went on Daylight Saving Time on April 30,1967 for the first time since World War II. Daylight Saving Time was rejected by the Arizona legislature in 1968. Arizona was exempted from the time change during the energy crisis in the winter of 1973-1974.
For the history of how Arizona decided not to participate in Daylight Saving Time, see the Tucson Citizen article "Arizona Long Ago Decided It Has Lots of Daylight, Thanks." (April 26, 1968. page A1.) Another good source of information is an article on the history of Arizona's rejection of Daylight Saving Time in "How Ticked-Off Arizona Got Rid of Daylight Saving," Arizona Daily Star, March 10, 2007 on page 1.
Why does most of Arizona reject Daylight Saving Time? One possible reason was explained by the now former chief meteorologist for KVOA-TV 4, Jimmy Stewart, "...the reason I hear most often is simply that we don't need another hour of sunlight in the heat of the summer."
Exceptions and Other Locations that Opt Out of Daylight Saving Time
Navajo Nation in northern Arizona does observe Daylight Saving Time.
In addition to Arizona, Hawaii and some U.S. territories do not observe DST.
"Arizona Exempted from the Time Change". Tucson Citizen. January 4, 1974. Page 1.
"Ask Jimmy." Arizona Daily Star. February 27, 2005. Page C14.
"Tucson Ready for Time Change." Arizona Daily Star. April 29, 1967. Page B1.
“Most of US resets time—not Arizonans." Arizona Daily Star. November 7, 2010. Page A2.
"Daylight Saving Time 2011: What About Arizona?, opens a new window" Phoenix Examiner. October 29, 2011. (NewsBank online resource.)
Daylight Saving Time, opens a new window | National Aeronautics and Space Administration (NASA), opens a new window
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