Aurora Borealis in Lerum
Sweden · 57.77°, 12.27° · geomagnetic 57.4° · needs Kp 7
Tonight's aurora forecast for Lerum
28%
Peak chance of a visible display tonight, from the same model the Revon app runs. Lerum needs Kp 7 to see anything at all, and tonight the forecast peaks at Kp 4.8. Short of the threshold, which is what most nights look like here.
Get the full 30-night forecast in Revon
Updated 2026-09-08 10:36 UTC
Local aurora guide for Lerum
Lerum is located at 57.4° geomagnetic latitude. Auroras visible at this latitude typically require a Kp index of 7 or higher.
Based on historical data from 2016 to 2026, there are approximately 2.4 nights per year in Lerum where conditions might be suitable for viewing an aurora.
The best months for aurora viewing in Lerum are September, November, and March. These months offer a good balance of darkness and potential aurora activity.
During May, June, and July, Lerum experiences periods without full darkness, which can significantly reduce the chances of seeing an aurora.
Lerum has a Bortle scale rating of 6, indicating a suburban sky with moderate light pollution. Darker skies, rated Bortle 4, can be found approximately 26 km north near Ale kommun.
Areas with Bortle 5 skies are located about 14 km east near Bollebygds kommun.
Notable features in the vicinity include the lake Lensjön 8.0 km east-north-east, and the lake Stora Lövsjön 10.5 km north of Lerum.
In the vicinity of Lerum, features such as Lensjön lake are located 8.0 km east-north-east. Stora Lövsjön lake is situated 10.5 km north.
Further afield, the island of Sunnerö is 13.8 km north-north-east, and the mountain Storåsen is 15.7 km north.
The island of Bokö is located 16.8 km north-north-east of Lerum.
Between 2016 and 2026, there were approximately 2.4 nights per year in Lerum suitable for aurora viewing. The record span for this data is from April 2, 2016, to March 30, 2026.
Aurorasaurus reports 23 verified sightings within 300 km of Lerum between January 1, 2015, and December 31, 2016.
Recent qualifying nights include March 20, 2026 (Kp 7.0), January 20, 2026 (Kp 7.67), January 19, 2026 (Kp 8.67), November 12, 2025 (Kp 7.33), and November 11, 2025 (Kp 8.67).
Sources: Revon location dataset · Revon analysis of NOAA planetary Kp · Solar declination and hour-angle calculation · Falchi 2016 World Atlas of artificial night sky brightness · GeoNames (CC BY 4.0) · Aurorasaurus verified positive reports
Know when it is worth going outside
Revon watches the Lerum forecast and pushes an alert when the odds for tonight clear your threshold — no checking, no guessing.
Nearby towns
Forecasts for places within reach of Lerum.