Set the alarm clock for 4:38 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 4:36 am Alarm clock for 4:37 am Alarm clock for 4:39 am Alarm clock for 4:40 am

Going to bed for a 4:38 am alarm

Asleep by 7:23 pm — 6 full sleep cycles, about 9 hours
Asleep by 8:53 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:23 pm — 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.

4:38 am across the country

London	4:38 am
Birmingham	4:38 am
Manchester	4:38 am
Glasgow	4:38 am
Belfast	4:38 am

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

How to use the online alarm clock

Waiting for 4:38 am gives you a fixed moment to check the tents after a storm in the Lake District without heading out too early. Keep an eye on the displayed time while you gather a torch and waterproofs. The alarm falls 22 minutes before 5:00 am, leaving a clear point to return and settle down.

While the tent check is pending, keep this alarm visible rather than leaving its page buried behind other activity. Browsers can reduce what a background page is allowed to do, which may delay its sound or make the on-screen change easy to miss. Set the volume beforehand and leave the page active. If the browser session ends or the phone falls asleep, the alarm cannot sound, so the tents may remain unchecked at the intended time.

Once the tent inspection is finished, protect the sleep that remains by preparing your return before 4:38 am arrives. Put dry footwear beside the entrance, keep the torch within reach and avoid switching on harsh overhead lighting. A short, quiet route back to bed makes it easier to deal with any wet pegs or loose guy lines without turning the night check into the start of the day.

Common questions

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.

Can I use this on a phone?

It works in a mobile browser, but phones lock the screen and suspend background tabs far more readily than a laptop does, which can stop the alarm sounding. For anything important, a desktop or a plugged-in laptop is the steadier option.

Does the alarm still work if I close the tab?

No. Everything runs inside this page, so closing the tab — or quitting the browser altogether — ends the countdown there and then. Leaving it open in the background is all it asks, and switching to another tab makes no difference.