How Daylight Saving Time Works (and Who Skips It)
Twice a year, hundreds of millions of people move their clocks by an hour, and for a few days afterwards somebody always turns up to a meeting at the wrong time. That's daylight saving time, or DST. Here are this year's dates, the places that ignore it completely, and the habits that keep it from catching you out.
What actually changes
For part of the year, usually the warmer months, clocks are set one hour ahead of the normal ("standard") time. The sun doesn't care, of course; it rises and sets exactly when it would have anyway. Only the number on the clock moves, which is why summer evenings feel an hour longer and mornings start an hour later by the clock.
You've probably heard "spring forward, fall back". In spring the clock jumps ahead and you lose an hour of sleep, and in autumn it drops back and you get that hour returned. A small pedantic point while we're here: it's daylight saving time, singular, even though "savings" turns up everywhere.
Why anyone started doing this
It spread during the First World War. Germany went first in 1916, and several other countries quickly copied it to make better use of daylight and burn less fuel. Plenty of places dropped it once the war ended, then brought it back later for much the same reasons. The argument about whether it still does any good comes round every year, and some countries have quit in the last few years, but most of North America and Europe still change their clocks.
When the clocks change in 2026
Each region has its own rule. We work these dates out from the same time zone data the rest of ClockDen runs on, so they update by themselves each year.
| Region | Clocks go forward | Clocks go back | Rule |
|---|---|---|---|
| USA and most of Canada | Sun, 8 March 2026 | Sun, 1 November 2026 | Second Sunday in March to first Sunday in November, at 2:00 AM local time |
| United Kingdom and most of Europe | Sun, 29 March 2026 | Sun, 25 October 2026 | Last Sunday in March to last Sunday in October, at 1:00 AM UK time |
| Eastern Australia (Sydney, Melbourne) | Sun, 4 October 2026 | Sun, 5 April 2026 | First Sunday in October to first Sunday in April (the southern summer) |
Australia runs the other way round, since its summer starts in December: clocks there go forward in October and back in April. If you book calls with Sydney, that's the detail to remember.
Most of the world doesn't bother
It's easy to assume everyone changes their clocks, but most countries don't. A few you're likely to deal with:
- India (UTC+05:30), China, Japan and most of Asia stay on the same time all year.
- Most of Africa skips it, as do countries near the equator, where the length of the day barely changes anyway.
- Arizona (except the Navajo Nation) and Hawaii stay on standard time all year.
- Brazil dropped DST in 2019, and most of Mexico followed in 2022.
- Iran stopped changing its clocks in 2022.
That's why the gap between two places isn't fixed. India is 9 hours 30 minutes ahead of New York in the US summer but 10 hours 30 minutes ahead in the US winter, and India didn't do anything; New York moved.
The awkward weeks in March and autumn
The US and Europe change on different dates. For about three weeks in March, and again for one week in late October or early November, the gap between New York and London is an hour smaller or bigger than usual. Those are the weeks when a standing call between the two quietly moves by an hour and someone ends up alone in an empty meeting. In 2026 Europe goes back on Sun, 25 October 2026, while the US waits another week and goes back on Sun, 1 November 2026.
Habits that stop the mix-ups
- Name a city instead of an abbreviation. "Eastern Time" covers both EST and EDT, but "New York" lets the software pick the right one.
- Check the date as well as the time, because a conversion that's right in January can be an hour off in July. Our Time Zone Converter lets you pick the exact date.
- Put both times in the invite, like "3:00 PM London / 10:00 AM New York", so nobody has to do the sum.
- Double-check anything that falls within a week of a clock change in either country.
- For three or more people, the Meeting Planner lays everyone's day side by side, so you can see who'd be asleep.
Does it even save energy?
Studies don't agree, and whichever way they land, the effect is small. Rules also change, and some places have voted to stay on one time all year, so for travel or anything legal it's worth checking an official source. For the live dates in a particular country, open it from the list of countries or see the time zone FAQ.