Is Kuopio or Iisalmi better for the northern lights?

Iisalmi sits closer to the oval, at 60.6 degrees geomagnetic against 59.9. Darkness, cloud and your dates decide the rest; the tables on this page show both towns month by month.

Which has longer nights in December, Kuopio or Iisalmi?

Iisalmi, with 16.8 hours of civil night on December 15 against 16.7 in Kuopio.

What Kp do Kuopio and Iisalmi need?

By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Kuopio needs about Kp 4 and Iisalmi Kp 3 for the average oval edge to sit overhead.

When is it too light for aurora in Kuopio and Iisalmi?

Kuopio: May 23 to July 19. Iisalmi: May 20 to July 22.

Which is clearer, Kuopio or Iisalmi?

Iisalmi, with 77% mean cloud in the months with 4 hours or more of civil night against 78% in Kuopio (NASA POWER, 2001 to 2020).

Comparison

Kuopio vs Iisalmi for the northern lights

Answer

Iisalmi sits 0.7 degrees higher on the IGRF-14 dipole, 60.6 against 59.9. By SWPC's oval-edge rule Iisalmi needs about Kp 3 for the average edge to sit overhead and Kuopio Kp 4. On the map Iisalmi is also closer to the pole, by 0.7 degrees.

59.9° / 60.6°

dipole latitude

Side by side

Computed figures for both towns
Figure	Kuopio	Iisalmi
Dipole latitude	59.9°	60.6°
Kp for the oval edge overhead	Kp 4	Kp 3
Civil night, December 15	16.7 h	16.8 h
Dark-season days	277	273
Nights with no civil darkness	58	64
Dark-month cloud, NASA POWER	78%	77%
Solar midnight, December 15	00:04	00:06

Kuopio sits at 59.9 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 4, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less. Iisalmi sits at 60.6 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.

Civil night month by month

On December 15 Kuopio has 16.7 hours of civil night and Iisalmi 16.8. Across the 15th of each month, Kuopio is darker in 3 months and Iisalmi in 3. The widest gap comes in May, when Kuopio has 0.7 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Kuopio	Iisalmi	Difference
January	15.9 h	16.0 h	-0.1 h
February	13.4 h	13.4 h	+0.0 h
March	10.6 h	10.6 h	+0.0 h
April	7.1 h	7.0 h	+0.1 h
May	2.8 h	2.1 h	+0.7 h
June	0.0 h	0.0 h	+0.0 h
July	0.0 h	0.0 h	+0.0 h
August	5.7 h	5.5 h	+0.2 h
September	9.3 h	9.3 h	+0.0 h
October	12.4 h	12.4 h	+0.0 h
November	15.1 h	15.2 h	-0.1 h
December	16.7 h	16.8 h	-0.1 h

Difference: Kuopio minus Iisalmi. Each figure links to that town's month page.

Season and midnight sun

Kuopio has no civil darkness from May 23 to July 19, 58 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 277 days. Iisalmi has no civil darkness from May 20 to July 22, 64 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 273 days.

Distance, cloud and time zones

The two towns are 78 km apart by great circle. In the dark months both average about 77% cloud in NASA POWER's 2001 to 2020 record. Kuopio's best month by civil night times clear sky is January. Iisalmi's best month by civil night times clear sky is January. Time zones: Europe/Helsinki and Europe/Helsinki.

For tonight, open the live pages for Kuopio and Iisalmi, which carry the live OVATION cell.

Questions

Is Kuopio or Iisalmi better for the northern lights?: Iisalmi sits closer to the oval, at 60.6 degrees geomagnetic against 59.9. Darkness, cloud and your dates decide the rest; the tables on this page show both towns month by month.
Which has longer nights in December, Kuopio or Iisalmi?: Iisalmi, with 16.8 hours of civil night on December 15 against 16.7 in Kuopio.
What Kp do Kuopio and Iisalmi need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Kuopio needs about Kp 4 and Iisalmi Kp 3 for the average oval edge to sit overhead.
When is it too light for aurora in Kuopio and Iisalmi?: Kuopio: May 23 to July 19. Iisalmi: May 20 to July 22.
Which is clearer, Kuopio or Iisalmi?: Iisalmi, with 77% mean cloud in the months with 4 hours or more of civil night against 78% in Kuopio (NASA POWER, 2001 to 2020).

Sources and verification

IGRF-14 coefficients, NOAA NCEIhttps://www.ngdc.noaa.gov/IAGA/vmod/coeffs/igrf14coeffs.txt
SunCalchttps://github.com/mourner/suncalc
GeoNameshttps://www.geonames.org/export/
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora

Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.