If you hear Hesa Fredrik, the outdoor warning signal, go indoors, close all doors, windows and ventilation if you can, and listen to Sveriges Radio P4. The signal for Important Public Announcement sounds for seven seconds, is silent for fourteen, and repeats for at least two minutes. A single continuous tone of about 30 to 40 seconds is the all-clear. It is tested four times a year, at 15:00 on the first non-holiday Monday in March, June, September and December, so if you hear it then it is almost certainly a test.
Reviewed by Oskar Björk, adviser and co-founder of Kapsel, defence engineer at the Swedish Armed Forces (Försvarsmakten). Last updated 2026-09-21.
What Hesa Fredrik is
Hesa Fredrik is the nickname for Sweden's outdoor warning sirens. They are one of several ways an Important Public Announcement, in Swedish Viktigt meddelande till allmänheten or VMA, reaches you when something seriously threatens life, health, property or the environment. The sirens themselves carry no information. They exist to do one thing: make you stop, go inside, and go and find the message.
The official description of the signal and the sirens is published by MCF, Sweden's Agency for Civil Defence.
How the signals sound
| Signal | Sounds like | Means |
|---|---|---|
| Important Public Announcement | 7 seconds of tone, 14 seconds of silence, repeated for at least 2 minutes | Go indoors, close up, find the message |
| All clear | One continuous tone, roughly 30 to 40 seconds | The danger has passed for now |
The broken, repeating pattern is the one that matters. A steady unbroken tone is the all-clear, not the warning. If you are unsure which one you heard, treat it as the warning and check.
What to do in the first minute
- Go indoors. Any building, not necessarily your own.
- Close doors and windows, and shut off ventilation if you can. Many VMAs are issued for smoke or a gas release, where the air outside is the hazard.
- Find the message. Sveriges Radio P4 carries VMA. So do television and text TV, and the message is published online at krisinformation.se.
- Do not call 112 to ask what happened. Emergency lines need to stay open for people who are actually in danger.
- Tell the people around you. Neighbours who are asleep, elderly relatives, anyone wearing headphones.
The whole sequence takes under a minute if you have thought about it once in advance. That is the entire reason to read a page like this on a calm day.
When it is only a test
The sirens are tested four times a year so that faults are found before they matter. The test is always at 15:00 on the first Monday of March, June, September and December, and if that Monday is a public holiday the test moves a week later. During a test both signals are sounded, the warning first and the all-clear a few minutes afterwards.
The next scheduled test is Monday 7 December 2026 at 15:00. If you hear the sirens at 15:00 on that date, nothing is wrong. If you hear them at any other time, act on them.
The other ways a VMA reaches you
Sirens only cover parts of the country, mostly denser built-up areas, and they cannot be heard indoors everywhere. That is why a VMA goes out on several channels at once:
- To mobile phones, through SE-Alert, which sends a loud alert and a text message to phones in the affected area without you having to install anything.
- On radio and television, including Sveriges Radio P4 as the primary broadcast channel.
- Online, at krisinformation.se, which also publishes the national guidance on shelters, evacuation and warning systems.
Every one of those channels except the sirens depends on something: a charged phone, a working mobile network, mains power for a television. That is the gap worth closing.
The part most households get wrong
A warning is only useful if you can then receive the message. In a long power cut the television is dead, the broadband router is dead, and the mobile network runs on battery backup at the mast, which is measured in hours rather than days. FM radio is the channel that keeps working, because the transmitters are built to stay up and because a radio can run on a hand crank or a couple of batteries.
So the practical checklist is short. Keep a radio that does not depend on the grid. Keep a way to charge a phone. Know your local P4 station. Write it on paper, because you will not be looking it up on a dead phone.
A radio that works when nothing else does
Kapsel Core includes an emergency solar crank radio alongside light, power, cooking, warmth and first aid for seven days, reviewed by a defence engineer and quality-checked in Borås.
See Kapsel CoreWhere this fits in your preparedness
Warning and information is one of the basics, alongside water, heat, light and food. Read the wider picture in our guide to VMA and staying informed in a crisis, keep the lights and the phone alive with light and power in a crisis, and build the rest from the complete emergency-kit checklist. If the warning is followed by a real outage, see how to get through a week without power and water. Or go straight to the Kapsel Core.
Frequently asked questions
What does Hesa Fredrik mean?
It is the nickname for Sweden's outdoor warning sirens. When they sound the Important Public Announcement signal, it means you should go indoors, close doors, windows and ventilation, and listen to Sveriges Radio P4 for the actual message.
How does the Hesa Fredrik signal sound?
Seven seconds of tone, then fourteen seconds of silence, repeated for at least two minutes. The all-clear is different: one continuous tone of about 30 to 40 seconds.
When is Hesa Fredrik tested?
At 15:00 on the first non-holiday Monday in March, June, September and December. The next scheduled test is Monday 7 December 2026.
What should I do when I hear the signal?
Go indoors, close doors, windows and ventilation if you can, and find the message on Sveriges Radio P4, television, or krisinformation.se. Do not call 112 to ask what happened.
Is Hesa Fredrik the same as a VMA?
No. The VMA is the message. Hesa Fredrik is one of the ways you are told that a message exists. A VMA is also sent to mobile phones through SE-Alert and broadcast on radio and television, and many VMAs are issued without the sirens sounding at all.
Why do I need a radio if a VMA is sent to my phone?
Because the phone alert depends on a charged phone and a working mobile network. In a long power cut the masts run on limited battery backup. FM radio keeps working, and a crank or battery radio does not depend on the grid at all.
Sources: MCF on outdoor warning and Hesa Fredrik, MCF on VMA and other warnings, and krisinformation.se on shelters, evacuation and warning systems.