Is Tampere or Lahti better for the northern lights?

Tampere sits closer to the oval, at 59.2 degrees geomagnetic against 58.4. 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, Tampere or Lahti?

Tampere, with 16.3 hours of civil night on December 15 against 16.2 in Lahti.

What Kp do Tampere and Lahti need?

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

When is it too light for aurora in Tampere and Lahti?

Tampere: May 31 to July 10. Lahti: June 5 to July 6.

Which is clearer, Tampere or Lahti?

Lahti, with 74% mean cloud in the months with 4 hours or more of civil night against 76% in Tampere (NASA POWER, 2001 to 2020).

Comparison

Tampere vs Lahti for the northern lights

Answer

Tampere sits 0.8 degrees higher on the IGRF-14 dipole, 59.2 against 58.4. By SWPC's oval-edge rule Tampere needs about Kp 4 for the average edge to sit overhead and Lahti Kp 4. On the map Tampere is also closer to the pole, by 0.5 degrees.

59.2° / 58.4°

dipole latitude

Side by side

Computed figures for both towns
Figure	Tampere	Lahti
Dipole latitude	59.2°	58.4°
Kp for the oval edge overhead	Kp 4	Kp 4
Civil night, December 15	16.3 h	16.2 h
Dark-season days	287	291
Nights with no civil darkness	41	32
Dark-month cloud, NASA POWER	76%	74%
Solar midnight, December 15	00:20	00:12

Tampere sits at 59.2 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. Lahti sits at 58.4 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.

Civil night month by month

On December 15 Tampere has 16.3 hours of civil night and Lahti 16.2. Across the 15th of each month, Tampere is darker in 5 months and Lahti in 5. The widest gap comes in July, when Lahti has 0.6 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Tampere	Lahti	Difference
January	15.6 h	15.5 h	+0.1 h
February	13.3 h	13.2 h	+0.1 h
March	10.6 h	10.7 h	-0.1 h
April	7.4 h	7.5 h	-0.1 h
May	3.7 h	4.0 h	-0.3 h
June	0.0 h	0.0 h	+0.0 h
July	1.7 h	2.3 h	-0.6 h
August	6.1 h	6.3 h	-0.2 h
September	9.5 h	9.5 h	+0.0 h
October	12.4 h	12.3 h	+0.1 h
November	14.9 h	14.8 h	+0.1 h
December	16.3 h	16.2 h	+0.1 h

Difference: Tampere minus Lahti. Each figure links to that town's month page.

Season and midnight sun

Tampere has no civil darkness from May 31 to July 10, 41 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 287 days. Lahti has no civil darkness from June 5 to July 6, 32 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 291 days.

Distance, cloud and time zones

The two towns are 116 km apart by great circle. In the dark months Lahti averages 74% cloud and Tampere 76%, from NASA POWER's 2001 to 2020 record. Tampere's best month by civil night times clear sky is March. Lahti's best month by civil night times clear sky is March. Time zones: Europe/Helsinki and Europe/Helsinki.

For tonight, open the live pages for Tampere and Lahti, which carry the live OVATION cell.

Questions

Is Tampere or Lahti better for the northern lights?: Tampere sits closer to the oval, at 59.2 degrees geomagnetic against 58.4. 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, Tampere or Lahti?: Tampere, with 16.3 hours of civil night on December 15 against 16.2 in Lahti.
What Kp do Tampere and Lahti need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Tampere needs about Kp 4 and Lahti Kp 4 for the average oval edge to sit overhead.
When is it too light for aurora in Tampere and Lahti?: Tampere: May 31 to July 10. Lahti: June 5 to July 6.
Which is clearer, Tampere or Lahti?: Lahti, with 74% mean cloud in the months with 4 hours or more of civil night against 76% in Tampere (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.