When to Change the Clock for Daylight Saving Time

Woman reaching to turn off alarm clock
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Daylight Saving Time begins in the U.S. every year on the second Sunday in March. It happens in the wee hours of the morning when many of us are typically asleep: 2 a.m. It ends on the first Sunday in November, also two hours after midnight. 

If you have trouble remembering whether you need to set your clocks ahead or behind when Daylight Saving Time (DST) begins and ends, a catchy little phrase can help you remember: Spring forward, fall back. Here are a few other little details you might want to keep in mind. 

Daylight Savings Time or Daylight Saving Time?

Although many people refer to Daylight Saving Time in the plural — "savings" — it's actually singular. Use "Daylight Saving Time," not "Daylight Savings Time." 

Who Started This Anyway? 

Benjamin Franklin has been erroneously credited with inventing DST. What Franklin actually said was that if Parisians cared to get out of bed before noon, they might save some money on candles. The time change wasn't officially adopted in the U.S. until the passage of the Uniform Time Act in 1966. The Act only sets standards for rolling clocks back and forth in the spring and fall so all states uniformly do so. It doesn't mandate that all states have to and, in fact, Hawaii and most of Arizona have declined. Indiana held out until 2006 before climbing aboard. 

The Uniform Time Act 

Officially, the law requires businesses and timekeeping institutions to change clocks at 2:00 a.m. when DST changes occur. But this doesn't regulate you in your own home. You can change your clocks any time you like, at bedtime the night before or when you wake the following morning. In fact, you don't even have to do it at all if you don't want to. But businesses and schools will have changed their clocks so you won't be arriving anywhere on time unless and until you do.

If you live in the U.S. where DST is observed, set your clocks ahead by one hour when DST begins, and back one hour when DST ends.

People With Diabetes or Who Take Medications on a Time Schedule

People with diabetes who take insulin shots or who use insulin pumps and other automated insulin delivery devices should change their pump clocks during the day. Changing medical device clock settings on devices such as an OmniPod during the night can affect basal settings and cause blood sugars to go too high or too low.

If you take medications or insulin on a time schedule, talk with your doctor about how to safely change your clock so that you don't experience any possible side effects when DST changes occur.

Take It as a Friendly Reminder 

It's recommended that you use the cue of Daylight Saving Time to change the smoke alarm batteries in your home. A recent study revealed that although most dwellings have smoke alarms, only about two-thirds of them actually have working batteries, so they're useless.