Is Sundsvall or Härnösand better for the northern lights?

Härnösand sits closer to the oval, at 61.1 degrees geomagnetic against 61.0. 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, Sundsvall or Härnösand?

Härnösand, with 16.6 hours of civil night on December 15 against 16.5 in Sundsvall.

What Kp do Sundsvall and Härnösand need?

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

When is it too light for aurora in Sundsvall and Härnösand?

Sundsvall: May 26 to July 16. Härnösand: May 24 to July 18.

Which is clearer, Sundsvall or Härnösand?

Sundsvall, with 71% mean cloud in the months with 4 hours or more of civil night against 71% in Härnösand (NASA POWER, 2001 to 2020).

Comparison

Sundsvall vs Härnösand for the northern lights

Answer

Härnösand sits 0.1 degrees higher on the IGRF-14 dipole, 61.1 against 61.0. By SWPC's oval-edge rule Härnösand needs about Kp 3 for the average edge to sit overhead and Sundsvall Kp 3. On the map Härnösand is also closer to the pole, by 0.2 degrees.

61.0° / 61.1°

dipole latitude

Side by side

Computed figures for both towns
Figure	Sundsvall	Härnösand
Dipole latitude	61.0°	61.1°
Kp for the oval edge overhead	Kp 3	Kp 3
Civil night, December 15	16.5 h	16.6 h
Dark-season days	281	279
Nights with no civil darkness	52	56
Dark-month cloud, NASA POWER	71%	71%
Solar midnight, December 15	23:46	23:43

Sundsvall 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. Härnösand sits at 61.1 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 Sundsvall has 16.5 hours of civil night and Härnösand 16.6. Across the 15th of each month, Sundsvall is darker in 2 months and Härnösand in 1. The widest gap comes in December, when Härnösand has 0.1 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Sundsvall	Härnösand	Difference
January	15.8 h	15.8 h	+0.0 h
February	13.3 h	13.3 h	+0.0 h
March	10.6 h	10.6 h	+0.0 h
April	7.2 h	7.2 h	+0.0 h
May	3.1 h	3.0 h	+0.1 h
June	0.0 h	0.0 h	+0.0 h
July	0.0 h	0.0 h	+0.0 h
August	5.9 h	5.8 h	+0.1 h
September	9.4 h	9.4 h	+0.0 h
October	12.4 h	12.4 h	+0.0 h
November	15.1 h	15.1 h	+0.0 h
December	16.5 h	16.6 h	-0.1 h

Difference: Sundsvall minus Härnösand. Each figure links to that town's month page.

Season and midnight sun

Sundsvall has no civil darkness from May 26 to July 16, 52 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 281 days. Härnösand has no civil darkness from May 24 to July 18, 56 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 279 days.

Distance, cloud and time zones

The two towns are 42 km apart by great circle. In the dark months both average about 71% cloud in NASA POWER's 2001 to 2020 record. Sundsvall's best month by civil night times clear sky is December. Härnösand's best month by civil night times clear sky is December. Time zones: Europe/Stockholm and Europe/Stockholm.

For tonight, open the live pages for Sundsvall and Härnösand, which carry the live OVATION cell.

Questions

Is Sundsvall or Härnösand better for the northern lights?: Härnösand sits closer to the oval, at 61.1 degrees geomagnetic against 61.0. 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, Sundsvall or Härnösand?: Härnösand, with 16.6 hours of civil night on December 15 against 16.5 in Sundsvall.
What Kp do Sundsvall and Härnösand need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Sundsvall needs about Kp 3 and Härnösand Kp 3 for the average oval edge to sit overhead.
When is it too light for aurora in Sundsvall and Härnösand?: Sundsvall: May 26 to July 16. Härnösand: May 24 to July 18.
Which is clearer, Sundsvall or Härnösand?: Sundsvall, with 71% mean cloud in the months with 4 hours or more of civil night against 71% in Härnösand (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.