Daylight saving time explained

POSTED: 12:22 PM Nov 04 2011   UPDATED: 10:59 AM Oct 30 2015

Daylight saving time begins this weekend. What's behind the tradition of pushing our clocks ahead each spring and setting them back each autumn?

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Toni Mihailov/

Contrary to popular belief, no federal rule mandates that states or territories observe daylight saving time.