Daylight Saving Time

What is daylight saving time?

Daylight saving time (DST, or “summer time”) moves clocks forward — usually by one hour — in spring and back in autumn, shifting an hour of daylight from the morning to the evening. Most of North America and Europe observe it, as do parts of South America and Australia, New Zealand and a few other countries. Most of Asia and Africa, including India, Japan, China and the Gulf states, do not.

Dates differ between regions: the United States changes clocks on the second Sunday in March and the first Sunday in November, while the European Union changes on the last Sundays of March and October. In the southern hemisphere DST runs during the northern winter. Rules change occasionally, so this page computes transitions from the IANA time zone database in your browser instead of a hardcoded list.

Example

In New York, clocks go from 01:59:59 EST (UTC−5) straight to 03:00:00 EDT (UTC−4) on the spring change, so 02:30 does not exist that day. In autumn, the clock goes from 01:59:59 EDT back to 01:00:00 EST, so 01:30 happens twice. The time zone converter warns about both cases.