Learn • Beginner

What Is Daylight Saving Time?

Why a billion people move their clocks twice a year — and why most of the world doesn’t bother.

4 min read

Daylight Saving Time (DST) shifts clocks forward one hour in spring and back in autumn, moving an hour of daylight from morning to evening during the longer days of summer.

When Clocks Change

RegionSpring forwardFall back
United States & Canada2nd Sunday of March1st Sunday of November
UK & European UnionLast Sunday of MarchLast Sunday of October
Australia (SE states)1st Sunday of October1st Sunday of April

Note the mismatch: for a few weeks each spring and autumn, the US has changed but Europe hasn’t (or vice versa), temporarily shifting the transatlantic gap. Exact 2026 dates: DST guide.

Who Skips DST

Most of the world: India, China, Japan, Russia, and nearly all of Asia, Africa, and the Gulf keep fixed time year-round — as do Hawaii and most of Arizona inside the US. Full list: countries without DST.

Why It Matters for International Calls

When only one side of a meeting observes DST, your gap shifts twice a year. US–India meetings move one hour in IST every March and November. Plan around it with the meeting planner.

DST Dates 2026 → No-DST Countries → Meeting Planner →

Frequently Asked Questions

Why does daylight saving time exist?

To shift an hour of summer daylight from early morning (when most people are asleep) to the evening, historically motivated by energy saving and daylight use.

When does DST start in the US?

US clocks spring forward on the second Sunday of March at 2 AM and fall back on the first Sunday of November.

Does India observe daylight saving?

No. India keeps IST (UTC+5:30) fixed all year, like most of Asia.