Set the alarm clock for 6:39 am

Leave this tab open — the alarm only rings while the tab stays open.

The alarm goes off in: ::

You can also try the other alarm clocks

Alarm clock for 6:37 am Alarm clock for 6:38 am Alarm clock for 6:40 am Alarm clock for 6:41 am

Going to bed for a 6:39 am alarm

Asleep by 9:24 pm — 6 full sleep cycles, about 9 hours
Asleep by 10:54 pm — 5 full sleep cycles, about 7 hours
Asleep by 12:24 am — 4 full sleep cycles, about 6 hours

A sleep cycle runs about 90 minutes, and most people take around 15 minutes to drop off. Waking at the end of a cycle feels easier than waking in the middle of one.

6:39 am across the country

London	6:39 am
Birmingham	6:39 am
Manchester	6:39 am
Glasgow	6:39 am
Belfast	6:39 am

Times are worked out live in your browser, so daylight saving is already accounted for.

How to use the online alarm clock

Finishing the preparations at the public pool at 6:39 am leaves enough time to lock the plant room, check the changing area and head away before the early session begins. Set the alarm for this precise time so the handover does not drift towards 7:00 am, when swimmers and the next member of staff may already be arriving.

While the pool checks are under way, this alarm page may sit behind another browser tab. It should remain ready in the background, although browser settings can sometimes reduce activity on pages that have not been visible for a while. Keep the sound level audible and return to the alarm page shortly before 6:39 am if the timing matters. The pool alarm will not sound after the page has been closed or the computer has gone to sleep, so use a separate alarm if you intend to shut everything down before leaving.

Leaving the pool this early can still preserve a useful stretch of sleep rather than turning 6:39 am into the start of the whole day. Prepare keys, clothes and anything needed for the journey home beforehand, then keep lights and phone use low once the final checks are complete. A straightforward wind-down makes it easier to treat the opening duty as a brief interruption and settle back into the sleep that remains.

Common questions

What happens if my laptop goes to sleep before 6:39 am?

The tab sleeps along with it and the alarm will not sound on time, if at all. If you are relying on it, change the power settings so the machine stays awake, or keep a phone alarm running as well.

Do I need an account or an app?

Neither. Choose a time and a sound, press Start, and it runs in this browser tab. Nothing is downloaded, nothing is registered, and closing the page leaves nothing behind on the device.

Can I change the sound?

Yes, there is a short list of tones to pick from before you press Start. Softer sounds are easy to sleep through, so a firmer bell tends to be the safer choice for anything early in the morning.

Will it still be right when the clocks change?

Yes. It reads your device's local clock, so the move between GMT and BST at the end of March and October is picked up automatically, as long as the computer's date, time and time zone are set correctly.