# Clock change (summer time)

The day a country moves its clocks forward an hour for summer, or back for winter. Many countries never do, and some have stopped.

## Where it comes from

Summer time was first used across a whole country during the First World War. In the time-zone database, Berlin’s clocks first went forward on 30 April 1916.

## An example

In late March your weekly call to Delhi seems to come an hour early, because London has moved its clocks and Delhi has not.