Aurora Borealis in Sastamala
Finland · 61.35°, 22.91° · geomagnetic 59.1° · needs Kp 5
Tonight's aurora forecast for Sastamala
44%
Peak chance of a visible display tonight, from the same model the Revon app runs. Sastamala 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 Sastamala
Sastamala is located at 59.1° geomagnetic latitude. Auroras are typically visible when the planetary Kp index reaches 5.
With an average of 20.1 viable nights per year, patient observers may have opportunities to witness the aurora.
The period between 2016 and 2026 has recorded aurora activity.
The best months for aurora viewing in Sastamala are September, March, and October.
These months offer the necessary darkness for aurora observation.
From May through August, the region experiences periods without full darkness, which can impact viewing conditions.
Sastamala has a Bortle scale rating of 5, indicating a suburban sky.
Areas with darker skies, rated Bortle 4, are located 24 km west-south-west near Kokemäki.
Other areas with Bortle 5 ratings are found 12 km south-south-east near Sastamala.
Koivusaari, an island, is located 3.0 km east-north-east of Sastamala.
Romminvuori, a hill, is situated 3.0 km north of Sastamala.
Vastamäki, another hill, lies 3.1 km north-west of Sastamala.
Between 2015 and 2016, 37 verified aurora reports were recorded within 300 km of Sastamala.
The historical data includes qualifying nights such as March 24, 2026, at Kp 5.0, and March 23, 2026, also at Kp 5.0.
Other recorded qualifying nights include March 22, 2026, at Kp 6.67, March 21, 2026, at Kp 6.0, and March 20, 2026, at Kp 7.0.
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 Sastamala 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 Sastamala.