Aurora Borealis in Forssa
Finland · 60.81°, 23.62° · geomagnetic 58.5° · needs Kp 5
Tonight's aurora forecast for Forssa
40%
Peak chance of a visible display tonight, from the same model the Revon app runs. Forssa needs Kp 5 to see anything at all, and tonight the forecast peaks at Kp 4.7. Short of the threshold, which is what most nights look like here.
Get the full 30-night forecast in Revon
Updated 2026-09-08 10:35 UTC
Local aurora guide for Forssa
Forssa is at 58.5° geomagnetic latitude. Auroras are typically visible here when the planetary Kp index reaches 5.
On average, there are 20.4 nights per year suitable for aurora viewing in this region. The historical record spans from April 2, 2016, to March 30, 2026.
The best months for aurora viewing in Forssa are September, March, and October. During these months, the nights are dark enough to potentially see the aurora.
However, from May to August, there is no full darkness due to the high latitude. This means that even if auroral activity is high, viewing conditions may not be optimal during these summer months.
Forssa has a Bortle scale rating of 6, indicating significant light pollution. For darker skies, areas like Humppila, 29 km north-west, offer a Bortle 4 rating, while Tammela, 10 km south-east, is rated Bortle 5.
Local terrain features include hills like Lamminmäki and Iidankallio, lakes such as Mäkilammi and Särkilammi, and a headland named Kolkannokka. These features are located within a few kilometers of Forssa.
In the vicinity of Forssa, notable terrain features include Lamminmäki, a hill located 3.1 km north-west, and Mäkilammi, a lake 3.2 km north-west.
Further points of interest include Iidankallio, a hill 3.3 km west, and Kolkannokka, a headland 3.3 km east. Särkilammi, a lake situated 4.3 km west-north-west, is also present in the area.
Within a 300 km radius of Forssa, there have been 40 verified aurora reports between January 1, 2015, and December 31, 2016.
The historical data indicates that nights with a Kp index of 5.0 or higher occurred on March 20, 21, 22, 23, and 24, 2026.
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 Forssa 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 Forssa.