Twice a year Sweden changes its clocks by one hour. It is easy to forget which way, so here is the simple version, plus why we do it at all and why it keeps not being abolished.
The English memory rule is "spring forward, fall back". A more physical one, if you have a garden: the furniture goes out when the clocks go forward, and comes in when they go back.
The change is deliberately placed in the small hours of a Sunday. Almost nothing is running, few people are mid-shift, and turning the clock back at 03:00 rather than at midnight avoids repeating a calendar date.
This is the part most people have backwards. Sweden's real time zone is Central European Time, one hour ahead of UTC, and that is what we use from late October to late March. It is not "winter time", it is simply the time zone.
Summer time is the deviation: for about seven months we run one hour ahead of our own zone. So we spend more of the year on the adjusted time than on the real one, which is one of the odder arguments in the whole debate.
The idea is to move daylight to where people are awake. Sunrise in June happens well before most of the country gets up, and shifting the clock forward transfers an hour of that light to the evening instead.
Sweden first tried it in 1916, disliked it, and dropped it after a single year. It returned in 1980, and has been coordinated across the EU since 1996 so that the entire union changes on the same dates. That coordination matters more than it sounds: before it, timetables and trading hours across Europe drifted apart for weeks at a time.
The original argument was saving energy, mainly on lighting. Modern studies find the effect close to zero. Lighting is a much smaller share of consumption than it was in 1916, and any evening saving tends to be offset by heating in a darker morning.
The hour itself is trivial. The disruption is not entirely.
The spring change is the harder one, since it removes an hour of sleep on a night before a working week. Research has repeatedly found a small rise in traffic accidents and heart attacks in the days that follow, and a measurable dip in sleep quality for around a week. The effects are small at an individual level but visible across a population.
The autumn change is gentler, though the sudden darkness at four in the afternoon lands harder in Sweden than in most of Europe.
Anything that knows what day it is handles the change on its own. Phones, computers, tablets, smart watches and television boxes all sync against a time server and adjust while you sleep. So does anything on the mobile network, and most modern cars with a connected navigation system.
What you tend to be left with is the oven, the microwave, the coffee machine, the bedroom alarm clock, older wristwatches, the car if it is not connected, and the clock on the wall. The reliable trick is to walk the flat once on the Sunday rather than discovering each one over the following week.
One thing worth checking in autumn: an alarm on a device that did not update will go off an hour early on Monday, which is a strange way to start a week.
In 2018 the European Commission ran a public consultation. Around 4.6 million people responded, an unusually large number, and a large majority wanted the twice-yearly change gone. The European Parliament voted in 2019 to abolish it from 2021.
Then it stopped. Abolition requires the member states to agree on what to abolish it in favour of, and they have not. Permanent summer time gives light evenings but very dark winter mornings, with sunrise after nine in northern Sweden. Permanent standard time gives workable mornings but sunset before nine at midsummer, which southern Europe dislikes. Neither option suits a union stretching from Finland to Portugal, and a patchwork where neighbours choose differently would be worse than the current arrangement.
So the change continues, not because anyone defends it, but because no alternative can command a majority.
Nollan.se shows the correct local time automatically, across the change included, so you never have to wonder whether a clock is an hour off.
Forward. On the last Sunday in March, 02:00 becomes 03:00, so the night is one hour shorter. In autumn it is the reverse: on the last Sunday in October, 03:00 becomes 02:00 and the night is one hour longer.
Yes. Standard time is Sweden's actual time zone, Central European Time, one hour ahead of UTC. Summer time is the deviation from it, not the other way round. The word "vintertid" is common in everyday speech but slightly misleading, since it is simply normal time.
No. Phones, computers and anything connected to the internet update themselves. What you generally do have to change by hand is the oven, the microwave, the car, wall clocks and older wristwatches.
To disturb as little as possible. At 02:00 on a Sunday almost no trains are running, few people are working a shift change and the date does not shift. Turning the clock back at 03:00 rather than midnight also avoids repeating a date.
Not in a binding way. Parliament voted in favour of abolition in 2019, but the member states never agreed on whether to settle on permanent summer time or permanent standard time, and the proposal has been stuck ever since. Until they agree, the change continues exactly as before.