Four times per year the IPA (Important Public Announcement) – also called Hesa Fredrik – is tested. The outdoor warning system is tested at 15.00 (3 pm) on the first non-public holiday Monday (7th March, 13th June, 5th September, 5th December). The signal will sound for 7 seconds, with 14 second breaks, for a total of 6 times. Afterwards, the “danger over” signal is also tested, which is an uninterrupted 30-second signal.

https://www.krisinformation.se/en/finding-help-and-services/emergency-warning