Why do we have daylight saving time?
Quick answer
Daylight saving time (DST) moves clocks forward one hour in spring and back one hour in autumn so that more daylight falls in the evening during the warmer months. It was first adopted widely during World War I to save fuel. In the US, DST runs from the second Sunday in March to the first Sunday in November.
Key facts
- US 2026 ended
- Sunday, November 1, 2026
- US 2027 starts
- Sunday, March 14, 2027
- EU/UK 2026 ended
- Sunday, October 25, 2026
- EU/UK 2027 starts
- Sunday, March 28, 2027
“Spring forward, fall back” is the easy way to remember which way the clocks go.
- 1784Benjamin Franklin jokingly suggests Parisians wake earlier to save candles
- 1895New Zealand scientist George Hudson proposes shifting clocks by two hours
- 1907British builder William Willett campaigns for summer time
- 1916Germany becomes the first country to adopt DST nationwide, during World War I; Britain follows weeks later
- 1966The US Uniform Time Act standardizes DST across most of the country
- 2007The US extends DST to its current March–November dates
Why it was introduced
The main goals were to save energy, especially coal and fuel in wartime, and to make better use of daylight in the evening when people are awake. Supporters today also point to more time for outdoor activities and shopping after work.
Who changes their clocks?
| Region | Dates |
|---|---|
| US and Canada (most areas) | Second Sunday in March → first Sunday in November |
| UK and EU | Last Sunday in March → last Sunday in October |
| Australia (some states) | First Sunday in October → first Sunday in April |
| No DST | Most of Asia and Africa, and US states Arizona (except the Navajo Nation) and Hawaii |
Why it’s debated
Studies suggest the energy savings are small today. The spring change, which costs an hour of sleep, has been linked to a short-term rise in car accidents and heart attacks. Sleep experts often favor permanent standard time, while others want permanent DST for brighter evenings. In the US, proposals like the Sunshine Protection Act have been debated in Congress, and the EU has discussed ending clock changes, but at the time of writing the switches continue.
Not sure what time it is right now? Check what time zone you’re in.
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