Will my alarm change when the clocks go back?

Short answer: no. When the clocks go back — on Sunday 25 October in the UK and most of Europe, and on Sunday 1 November in the US and Canada — an alarm set for 6:30 on your phone still rings at 6:30 by the clock on your wall. You do not need to change anything.

There is one hour on that night where it gets genuinely confusing, and a few things around the phone that can still catch you out. Here is what is worth checking.

Why your alarm does not move

An alarm on your phone is set in local time: "6:30", not "a certain number of hours from now". The rules for when the clocks change are built into the phone itself, so on the night of the change it simply shifts its own clock and carries on. Every alarm keeps its time on the dial.

That also means the clock change does not need the internet. Unlike crossing a time zone, which the phone usually learns from the mobile network, the switch to winter time happens on the phone even in flight mode. (If you are travelling as well, the time zone is a separate question.)

The hour that happens twice

When the clocks go back, one hour of the night happens twice:

• In the UK, 01:00 to 02:00.

• In most of Europe, 02:00 to 03:00.

• In the US and Canada, 01:00 to 02:00.

An alarm set inside that hour is the one case where apps can behave differently — it might ring once, or on some apps twice. Almost nobody sets a wake-up alarm at 1:30 in the morning, so for most people this never comes up. If you do have something in that hour on change night, the simplest fix is to move it outside the hour for that one night.

In spring the opposite happens: an hour is skipped, and an alarm set inside the missing hour has no time to ring at. Again, this only matters for alarms in the middle of the night.

Three things that do catch people out

1. A phone whose time is set by hand. Phones change the clocks automatically when the date and time are set automatically, which is the default. If you once switched that off — to fix a game, or after a trip — your phone will not change on its own. Check it in your date and time settings before the weekend.

2. The other clocks in the room. Your phone will be right on Sunday morning. An old bedside alarm clock, the oven or the car may not be, and the first clock you look at when you wake up is often the wrong one. If you rely on a separate alarm clock, change it before you go to bed on Saturday.

3. A week when the gap between countries is wrong. Europe and North America change on different weekends. Between 25 October and 1 November, London is four hours ahead of New York instead of five, and Paris or Berlin five instead of six. If you have calls, flights or plans across the Atlantic that week, check the time in the other place rather than doing the usual sum in your head.

The morning after

When the clocks go back, a 6:30 alarm rings when your body thinks it is 7:30. It is the gentlest morning of the year, and a good one to start getting up on time if you have been putting it off.

Spring is the other way round: on the last Sunday in March in Europe and the second Sunday in March in the US, 6:30 feels like 5:30. That is the morning when people are most tempted to press snooze. If you have an early start that week, plan for it rather than finding out at 6:30.

How Waky handles it

Waky stores every alarm the same way the clock app does: a time of day and the time zone it belongs to. So 6:30 stays 6:30 through the clock change, and through travel too. The alarm is scheduled on your phone, so nothing about the change depends on a connection.

Your streak counts mornings by your local calendar, so the night the clocks change is just another night. Get up on the Sunday and it counts like any other morning; there is no lost or extra day to worry about.

If an alarm on Android ever does stay quiet, it is far more likely to be a battery setting than the clock change — here is how to fix that, brand by brand. And on iPhone, the usual suspects are on this checklist.

The short version

• Your phone alarm keeps its time when the clocks change. Leave it alone.

• Avoid setting an alarm in the repeated hour on change night.

• Check that your phone's date and time are set automatically.

• Fix any separate alarm clock before bed on Saturday.

• Double-check times across the Atlantic between 25 October and 1 November.