Northern lights in Tromsø in September
63%
of 4-night stays in September saw the northern lights at least once, by our estimate. On any one night the chance was 27%. September is a good month in Tromsø, though January (75%) was better.
How long to stay in September
Chance of at least one good night, by length of stay, Tromsø in September, 2015–2025. 6 nights got you to about 3 in 4.
In a typical September, the longest run of nights without a single clear, dark hour was 9 nights. A stay shorter than that can fall entirely into one cloudy spell.
Week by week in September (4-night stay)
- 2 Sep – 8 Sep66%
- 9 Sep – 15 Sep65%
- 16 Sep – 22 Sep62%
- 23 Sep – 29 Sep60%
September in Tromsø, year by year
Good nights in September, each year 2015–2025. The typical September had 8 good nights; the worst, 2023, had 3 and the best, 2017, had 17.
A good night = at least one hour that was dark (sun below −12°), mostly clear (NASA POWER cloud data, calibrated on FMI weather stations) and had a Kp index at or above the Kp 1 that Tromsø needs (GFZ Potsdam). These are estimates, not sightings. How it works
Other destinations in September
Tromsø ranks 7th of 21 popular aurora destinations for September (4-night stays, 2015–2025).
Yellowknife
94%Churchill
92%Alta
71%Lofoten
69%Kilpisjärvi
67%Abisko
65%Aurora tours in Tromsø in September
A guide with a car can drive to wherever the clouds break. With cloudy spells of 9 nights in a typical September, that matters here. Booking for your first night leaves the rest of the stay to try again if it's cloudy.
Tromsø in September: questions
September is a good month in Tromsø, though January (75%) was better. In 2015–2025, 63% of 4-night stays in September saw the northern lights at least once, and an average September had 8 good nights (clear, dark and with auroras strong enough) out of 30. These are estimates from NASA cloud records and the Kp index, not sightings.
2 nights gave 43%, 4 nights gave 63%, 7 nights gave 80% odds of at least one good night in September (2015–2025). For about 3-in-4 odds, plan 6 nights or more. In a typical September, the longest run of nights without a single clear, dark hour was 9 nights. A stay shorter than that can fall entirely into one cloudy spell.
About 5.6 hours a night with the sun more than 12° below the horizon, which is dark enough for faint auroras. Of those, 1.3 hours a night were mostly clear on average, and 9 nights in an average September had at least one clear, dark hour.
Auroras can appear any time it's dark, but activity usually peaks around midnight, roughly 22:00 to 02:00. With about 5.6 hours of darkness a night in September, start looking as soon as it's dark and stay out past midnight if you can. The live forecast shows tonight's best hour.