CNN) -- It's time to "fall back" again. At 2 a.m. Sunday, you'll have to turn your clock back one hour, because it's the end of daylight saving time.
If you're in the United States, it applies to you -- unless you're in Hawaii and some parts of Arizona. Those are the only parts of the 50 states that don't observe daylight saving time. The territories of Guam, Puerto Rico, U.S. Virgin Islands and American Samoa do not observe it either.