When do the clocks go forward? In 2023 the clocks go forward on Sunday, March 26, marking the start of BST. The clock change always happens at 1am on the last Sunday of the month, so there is as little disruption as possible. That means, if you're awake at that time, you'll see the time on your phone automatically jump from 1am to 2am, which means you'll lose an hour of sleep