WRAL WeatherCenter Blog

The long, complex history of daylight saving

Posted November 11, 2021 6:12 p.m. EST
Updated November 12, 2021 10:17 a.m. EST

Every November and April we are reminded how many people don’t like daylight saving time (DST). Experts cite increased risks of car and pedestrian accidents and crime and point to increased risk of stroke in the days that follow a time change.

There's another reason to question the semiannual struggle to figure out how to change the clock on your microwave. The rules governing when we spring forward or fall back are just too complex, and we can't seem to make up our minds about them.

So many rules

Worldwide, there are currently more 20 different rules governing when to observe DST.

Some of the differences make sense. Countries in the southern hemisphere change their clocks in October, during their spring.

But here in the northern hemisphere, the start of DST varies between the first Sunday in April (Mexico) and the last Sunday in May (Casablanca, Morocco). Some start at 2 a.m. local, others at midnight or 1 a.m.

So many exceptions to those rules

In the United States we move our clocks forward the second Sunday in March and back again the first Sunday in November. Simple right? Except in Hawaii and Arizona where DST is not observed. Except, except in the Navajo nation northeastern corner of Arizona where it is. Except, except, except the Hopi reservation within Navajo lands, where it isn't. Confused? It gets worse.

daylight saving in the southwest

So many changes to those rules

Looking across the time zone database used by every smart phone and computer (except Windows where rules are managed by a team of self described "time lords" at Microsoft), the rules have changed nearly 3,000 times since daylight saving was first used in Germany in 1916.

In the eastern timezone alone (your computer knows it as America/New_York mostly to enable unique daylight saving rules with the 24 standard timezones), the rules have changed eight times:

  • 1918: last Sunday in March to the last Sunday in October
  • 1921: last Sunday in April to last Sunday in September
  • February 9, 1942, to September 30, 1945 (World War II)
  • 1974: first Sunday in January to last Sunday in October
  • 1975: last Sunday in February to last Sunday in October
  • 1976: last Sunday in April to last Sunday in October
  • 1987: first Sunday in April to last Sunday in October
  • 2007-today: second Sunday in March to first Sunday in November

The entire United States, excluding Hawaii, observed year-round Daylight Saving Time from Feb. 9, 1942, to Sept. 30, 1945, known as "War Time." We returned to the 1921 rule in 1946.

Worldwide these changes have been driven by war or energy crises and sometimes just politics.

The Turkish government postponed the time change in 2015 until after an election, with just a week's notice, creating chaos. The South Pacific Island of Fiji recently announced it would not be changing its clocks as planned last weekend, the third change since the country began observing it in 1998.

Legislating time

Every state except Rhode Island and Indiana (which has a maddeningly complex history with daylight saving) has taken up the issue of making daylight saving permanent. Fifteen have passed bills.

daylight saving legislation nationwide

North Carolina lawmakers introduced House Bill 307 in April to keep the state on daylight saving time year-round. But as North Carolina Rep. Jason Saine, R-Lincoln, notes, they're meant to send a message to Congress. No state law can take effect until the subject is taken up by Congress.

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