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Guide

Northern Lights in Rovaniemi

Finland

Aurora needs a dark sky, enough geomagnetic activity and clear weather. This page covers all three for Rovaniemi, Finland, month by month.

Best Time to Go

January, February, March

Best months for an overhead display: January, February, March.

Overhead display
Kp 2 or higher

Tonight, Live

Checking tonight's aurora forecast...

Dark enough from September to March. Too light to see aurora from May to August.

At this latitude the aurora is usually within view low in the northern sky on dark nights, even when activity is low, so we do not give a horizon count here. It is not a promise of a display, and clear, dark skies are needed.

Best time of night: the aurora here is usually strongest around 12:30am standard time (1:30am while clocks are on summer time), from about 10:30pm to 2:30am standard time.

The activity counts here cover geomagnetic activity and darkness only, not clouds. Clear, dark skies are needed to see aurora.

How to Read This Page

Three things have to line up to see the northern lights: darkness, enough geomagnetic activity for the latitude, and a clear sky.

Dark hours are the hours each night with the sun more than 12 degrees below the horizon, read on the 15th of the month.

Activity is the Kp index, a 0 to 9 scale of geomagnetic activity measured every 3 hours. Each place needs a certain Kp for a faint glow to the north and a higher Kp for a display overhead. The counts show how often dark nights reached that level from 1991 to 2025.

The best months are the three months when the largest share of dark nights reached the level. They often fall around the equinoxes, in March and in September and October, rather than in midwinter: geomagnetic storms are more common then, because the tilt of the Earth's magnetic field around the equinoxes makes it easier for the Sun's magnetic field, carried by the solar wind, to connect with it.

The activity counts do not include clouds, and history is not a forecast. Check the live maps on the night, before you head out.

Source for the equinox effect: Russell and McPherron (1973), Semiannual Variation of Geomagnetic Activity, Journal of Geophysical Research.

Hours of Darkness Each Month

Mostly Clear Nights and Cold by Month

Month Mostly clear nights in a typical month Average lowAverage snow depth
January about 9 nights 3°F-16°C16 in41 cm
February about 8 nights 5°F-15°C21 in55 cm
March about 10 nights 12°F-11°C23 in58 cm
April about 6 nights 24°F-5°C13 in34 cm
May too light 36°F2°C2 in4 cm
June too light 46°F8°Cnonenone
July too light 53°F11°Cnonenone
August about 3 nights 49°F10°Cnonenone
September about 10 nights 42°F5°Cunder 1 in1 cm
October about 7 nights 30°F-1°C4 in11 cm
November about 8 nights 18°F-8°C7 in19 cm
December about 9 nights 9°F-13°C11 in27 cm

A mostly clear night here has at least 2 dark hours with under 50 percent cloud cover (a satellite estimate for the area), counted from 2001 to 2025.

Mostly clear nights and active nights are counted separately, so they are not always the same nights.

Cloud, low and snow figures are satellite and model estimates for the area around each place, 2001 to 2025, not readings from a local weather station. They are averages, not a forecast.

Biggest Nights on Record Here

  • November 11, 2025: Kp 9
  • October 10, 2024: Kp 9
  • November 9, 2004: Kp 9
  • November 7, 2004: Kp 9
  • October 30, 2003: Kp 9

The strongest dark nights here from 1991 to 2025, each strong enough for a display overhead at Rovaniemi. Clear, dark skies needed.

The Solar Cycle

In October 2024 NASA and NOAA announced that the Sun had reached the maximum period of Solar Cycle 25, which they said could last about a year. Source: NASA

Month by Month in Rovaniemi
Month Dark hours Nights reaching Kp 2 (overhead)
January 14.5 about 23 nights
February 11.8 about 22 nights
March 8.4 about 23 nights
April 2.7 about 13 nights
May none too light
June none too light
July none too light
August none too light
September 6.8 about 21 nights
October 10.7 about 23 nights
November 13.8 about 21 nights
December 15.3 about 22 nights

Nights in a typical month. Clear, dark skies needed.

Dark hours: time with the sun more than 12 degrees below the horizon on the night of the 15th. Kp needed: from the place's corrected geomagnetic latitude (AACGM-v2) and NOAA's average position of the auroral oval; the horizon figure adds our own allowance of about 3 degrees. Nights: definitive Kp, 1991 to 2025, counting only nights with darkness.

Kp index data: Geomagnetic Observatory Niemegk, GFZ Helmholtz Centre for Geosciences, CC BY 4.0. Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021. The geomagnetic Kp index and derived indices of geomagnetic activity. Space Weather, https://doi.org/10.1029/2020SW002641 CC BY 4.0

The month figures are history, not a forecast.

Cloud, temperature and snow data: NASA Langley Research Center (LaRC) POWER Project, funded through the NASA Earth Science/Applied Science Program. NASA POWER

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