Ostrobothnia, Finland
Northern lights in Korsholm
Answer
Tonight
Waiting on darkness
It is not civil-dark yet. The next dusk is listed below.
Observed 11:55 UTC, forecast 13:26 UTC, 91 min lead
Clock times in Europe/Helsinki
Storm level needed
Korsholm sits at 63.11N 21.68E in Ostrobothnia, Finland. The IGRF-14 centered dipole puts Korsholm at 61.0 degrees geomagnetic latitude, 2.1 degrees farther from the magnetic pole than its map latitude suggests. Korsholm sits at 61.0 degrees geomagnetic, inside SWPC's 60 to 75 degree band, where aurora can be seen on more than half of all nights. No storm is needed: by SWPC's rule the average oval edge is overhead at Kp 3.
"The best place to observe the aurora is under an oval shaped region between the north and south latitudes of about 60 and 75 degrees. At these polar latitudes, the aurora can be observed more than half of the nights of a given year."
The nearest other Glow towns are Vaasa (4 km), Kurikka (67 km), Seinäjoki (68 km). Vaasa sits 0.0 degrees lower on the dipole and needs the same Kp.
Approximate: SWPC calls its Kp to latitude rule an average, and a centered dipole can differ by a degree from fuller field models. How the storm level is matched
The year in darkness
From May 22 to July 20 the sun never reaches -6 degrees, so 60 nights in 2026 have no civil darkness at all. SWPC puts it plainly: "It must also be dark so during the summer months at auroral latitudes, the midnight sun prevents auroral observations." Glow's dark season, at least 4 hours of civil night between 18:00 and 06:00, runs from August 4 to May 7 across New Year, 277 days in 2026. Korsholm's longest night of the year, Dec 20, has 16 h 46 min of civil night.
Solar midnight at Korsholm, when the sun is lowest, falls at 00:28 on local clocks on December 15 and 01:34 on June 15. That is 28 min after midnight in December and 1 h 34 min after midnight in June, the gap set by daylight saving and the equation of time. So at Korsholm the darkest hour sits near the middle of SWPC's 10 PM to 2 AM window in winter.
Month by month
| Month | Night | Civil | Cloud | Clear dark | |
|---|---|---|---|---|---|
| Jan | 15.9 h | 12.1 h | 82% | 2.9 h | |
| Feb | 13.4 h | 9.8 h | 80% | 2.7 h | |
| Mar | 10.6 h | 6.7 h | 74% | 2.8 h | |
| Apr | 7.1 h | 0.0 h | 68% | 2.3 h | |
| May | 2.5 h | 0.0 h | 61% | 1.0 h | |
| Jun | 0.0 h | 0.0 h | 63% | 0.0 h | |
| Jul | 0.0 h | 0.0 h | 64% | 0.0 h | |
| Aug | 5.6 h | 0.0 h | 66% | 1.9 h | |
| Sep | 9.3 h | 5.0 h | 70% | 2.8 h | |
| Oct | 12.4 h | 8.8 h | 77% | 2.9 h | |
| Nov | 15.2 h | 11.4 h | 82% | 2.7 h | |
| Dec | 16.7 h | 12.7 h | 80% | 3.3 hbest |
By the 15th-of-the-month sample, December is the darkest month at Korsholm with 16.7 hours of civil night and June the lightest at 0.0. Across the year Korsholm gets 3,301 hours of civil night. Astronomical night at Korsholm, the sun 18 degrees or more below the horizon, lasts 12.7 hours on December 15.
NASA POWER's 2001 to 2020 all-hours climatology puts mean cloud amount for the 1 degree cell around Korsholm at 72% across the year, from 61% in May to 82% in January. In the months with at least 4 hours of civil night Korsholm averages 75%, against a median of 76% for Glow towns in Finland.
Multiplying civil night by the clear share of the sky gives December the best score, 3.3 hours, ahead of January at 2.9. Korsholm's equinox months score 2.8 in March and 2.8 in September, the weeks SWPC links with larger storms.
Kp history
From 1996 to 2025, the GFZ Potsdam record shows a 3-hour Kp of 3 or more, the level that puts the average oval edge over Korsholm, on 50% of days. At Korsholm's level the share runs from 43% in June to 58% in March, while storm days with Kp 5 or more made up 10%.
Share of UTC days in each calendar month whose highest 3-hour Kp reached Kp 3. Kp history by year
Moon, next 30 nights
Over the 30 nights from Oct 2, the new moon falls on Oct 10 and the full moon on Oct 26, in Europe/Helsinki dates. 15 of the 30 nights at Korsholm have at least 2 moon-free dark hours inside 10 PM to 2 AM, and Oct 6 has the most at 4 h. Tonight Korsholm has 11 h 6 min of civil night, 0 min of it with the moon down.
- 2
58% lit
0.0 h
- 3
47% lit
0.9 h
- 4
35% lit
3.3 h
- 5
25% lit
5.4 h
- 6
16% lit
7.3 h
- 7
9% lit
9.1 h
- 8
4% lit
10.9 h
- 9
1% lit
11.8 h
- 10
0% lit
11.9 h
- 11
2% lit
12.0 h
- 12
5% lit
12.1 h
- 13
10% lit
12.2 h
- 14
17% lit
12.3 h
- 15
25% lit
12.4 h
- 16
33% lit
12.5 h
- 17
43% lit
12.4 h
- 18
52% lit
10.1 h
- 19
62% lit
8.3 h
- 20
71% lit
6.6 h
- 21
79% lit
5.0 h
- 22
87% lit
3.5 h
- 23
93% lit
1.8 h
- 24
98% lit
0.1 h
- 25
100% lit
0.0 h
- 26
99% lit
0.0 h
- 27
96% lit
0.0 h
- 28
90% lit
0.0 h
- 29
81% lit
0.0 h
- 30
72% lit
0.0 h
- 31
61% lit
2.3 h
Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.
Within Finland
Among the 3 Glow towns in Ostrobothnia, Korsholm ranks 2nd by dipole latitude against a regional median of 61.0 degrees; Jakobstad sits highest at 61.4. Among the 66 Glow towns in Finland, Korsholm ranks 11th by dipole latitude against a national median of 59.1 degrees; Rovaniemi sits highest at 63.6. On December 15 Korsholm gets 16.7 hours of civil night, 12th longest of 66 in Finland, where the median is 16.3.
Questions
- Can you see the northern lights in Korsholm?
- Korsholm sits at 61.0 degrees geomagnetic, inside SWPC's 60 to 75 degree band, where aurora can be seen on more than half of all nights. No storm is needed: by SWPC's rule the average oval edge is overhead at Kp 3. Clear, dark sky over Korsholm still decides it.
- When is it dark enough in Korsholm?
- Civil night, the sun at -6 degrees or lower, is missing from May 22 to Jul 20. Tonight has 11 h 6 min of it.
- What is the best month for aurora in Korsholm?
- December, by civil night at Korsholm times the clear share of the sky from NASA POWER's 2001 to 2020 average.
- How cloudy is Korsholm in the dark months?
- About 75% mean cloud amount over Korsholm in the months with at least 4 hours of civil night, from NASA POWER's 2001 to 2020 all-hours climatology.
- How often is activity high enough for Korsholm?
- A 3-hour Kp of 3 or more, the level that puts the average oval edge overhead, occurred on 50% of days from 1996 to 2025 in the GFZ Potsdam record.
- Why does this page point to Vaasa?
- Korsholm sits within 15 km of Vaasa with the same rounded dipole latitude, Kp and dark season, so Glow treats Vaasa as the main page for both.
Nearby and related
Nearest Glow towns
Korsholm by month
Region and comparisons