DST Checker
Is daylight saving in effect?
Whether a zone is on summer time right now, when it next changes, and the exact instant of the change — found by search, to the millisecond.
How this is worked out
- Transitions are found by binary search against the runtime's own zone data, so the instant is exact rather than looked up from a rule.
Questions people ask
The things that come up about dst checkers, answered plainly.
When do the clocks change?
It varies by country and changes by legislation. The EU moves on the last Sunday in March and October; the US on the second Sunday in March and the first in November; Australia in October and April. The page finds the actual transitions for your zone rather than assuming a rule.
Which zones do not observe it?
Most of the world, in fact — all of Asia except a few, all of Africa except Morocco's Ramadan adjustment, and in the US, Arizona and Hawaii. Japan, India and China have never used it.
Related tools
Convert between zones, watch a board of cities, and find the hour that suits everyone.