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Nov 08, 2026

Polar night in Rovaniemi: the science of kaamos and its blue light

Polar night in Rovaniemi is one of the things our guests ask about most once they have booked a winter trip. Will it be dark all day? Will there be any light for photos? Is it depressing, or beautiful? In Finnish the season has its own word, kaamos, and in Lapland people talk about it the way others talk about the weather.

This is our explainer on the science behind it. The figures come from the Finnish Meteorological Institute, NASA, thisisFINLAND and Visit Rovaniemi, and they are listed at the end. We also explain how the dark season shapes the evening tours we run.

In short: the polar night is the period when, north of the Arctic Circle, the sun does not rise above the horizon at all. In the northernmost corner of Finland it lasts 51 days (FMI). Rovaniemi lies right at the Arctic Circle, so it is on the very edge of this zone. Around late December the city gets only a few hours of blue and pink twilight around midday rather than weeks of total darkness.

At a glance

• From: 109 €
• Experience type: Northern Lights tour / activity
• Duration: 3 hours
• Difficulty: Very easy
• Book in Advance: Cut off: 3 hours before start time
• Included: A Tour Guide in English (other languages available on request:  Spanish, Portuguese, French, Italian, German & Finnish.) PLEASE NOTE LIMITED AVAILABILITY FOR OTHER LANGUAGES). If another language is required. Please send us an email or WhatsApp after booking.); Winter clothing (Adult & Child size), overalls, boots, gloves, socks; Local snacks & Drinks by the campfire; Information about the Northern Lights; Surprise gift for the children; Pick-ups and drop-offs are included in the price in 10 km radius from Rovaniemi city center; Photos taken with your own device; Air conditioned car
• Cancellation: Free cancellation 24 hours before the activity. We will charge a cancellation fee of 100% if booking is cancelled less than 24 hours before the activity.
• Accessibility: Not wheelchair accessible; Not stroller accessible

What the polar night is

The Finnish Meteorological Institute defines it simply: north of the Arctic Circle, part of winter is the period known as the polar night, when the sun does not rise above the horizon at all. It is the mirror image of the midnight sun, when the sun does not set at all around midsummer.

The Finnish word kaamos is often used more loosely, for the whole dark stretch of winter. Visit Finland describes this soft darkness as usually peaking between November and mid-January. So when people in Rovaniemi say it is kaamos, they usually mean these weeks of very short days, not just the few days when the sun stays below the horizon.

Why it happens: Earth’s tilted axis

NASA sums it up in one sentence: Earth’s tilted axis causes the seasons. Because Earth’s axis doesn’t stand up straight, different parts of the planet receive the Sun’s most direct rays as we orbit through the year. Around December the South Pole is tilted towards the Sun and the north is tilted away.

The further north you are, the stronger the effect. Close to the Arctic Circle, the sun only just grazes the horizon at midwinter. Further north, it stays below the horizon for days and then weeks. Distance from the Sun is not the reason: NASA points out that the Northern Hemisphere has winter when Earth is actually closest to the Sun.

How long the polar night lasts in Finland

The length depends entirely on latitude:

• Northernmost Finland: 51 days of polar night, according to FMI. thisisFINLAND notes that in Utsjoki, on the northern border, it lasts for almost two months.
• Sodankylä: further south, close to the Arctic Circle, the polar night lasts for four days (thisisFINLAND).
• Rovaniemi: at the Arctic Circle itself, the city is on the edge. Visit Rovaniemi describes late December as the time when the sun doesn’t rise above the horizon and the Arctic Capital is bathed in deep blue and pink hues.
• Southern Finland: there is no polar night, but days are still short. In Helsinki the shortest day is less than six hours.

Why it is rarely pitch black

Most people expect the polar night to be as dark as midnight. It isn’t. As thisisFINLAND explains, Finnish Lapland is close enough to the Arctic Circle that, even with the sun below the horizon, sunlight still reaches the upper layers of the atmosphere and some ambient light gets through. Blue twilight is typical. The moon can light up the sky and the snow reflects it.

Snow matters a lot. FMI notes that the first snow in northern Finland falls in September, that winter usually begins in Lapland in mid-October, and that winter there lasts about 200 days. By the darkest weeks the ground is normally white, and it bounces every bit of light back up.

The blue moment

Photographers talk about the blue hour. In Rovaniemi, Visit Rovaniemi notes, locals often call it the blue moment instead, because in midwinter it can be very brief. For a few hours around midday the snowy landscape turns blue, violet and pink as the sun’s light scatters from below the horizon.

Our practical advice: if you want daylight photos in December, plan to be outdoors in the middle of the day and keep the evening for the sky.

Polar night and the Northern Lights

The dark season and the aurora are often mixed up, so here is the distinction. The polar night does not cause the Northern Lights. Auroras come from the Sun’s activity, which we explain in How are auroras formed?. What long nights do is give you more dark hours in which to see a display. FMI notes that the typical time for auroral displays is around midnight and a couple of hours either side, and that at Lapland ski resorts auroras can be seen on roughly 50 % of dark, cloudless nights.

The limit is usually cloud, not darkness. That is also why FMI names March and early April as the best time to see auroras in northern Finland. We look at the other end of the season in Equinox aurora: the science behind active September and March skies.

How this shows up on our tours

Long dark evenings are when our aurora tours happen. In the polar night weeks we most often recommend the Northern Lights Tour in Atmospheric Cottage (from 109 €, 3 hours). It is a traditional cottage more than 100 years old beside Lake Poikajärvi, on our private land about 20 minutes from the city. Your guide explains the Northern Lights by the campfire, winter clothing is included, and there is a warm room when the cold gets to you. It starts at 20:00. The Northern Lights can never be guaranteed on this tour.

If you prefer a teepee and campfire setting, there is the Northern Lights Tour At The Campfire (from 99 €, 3 hours). If you want to chase clear skies with a refund if no auroras are captured, choose the guaranteed bus tour (from 109 €) or the small-group guaranteed hunt (from 199 €, groups of 2–8).

Frequently asked questions

Is there polar night in Rovaniemi?

Rovaniemi lies right at the Arctic Circle, on the edge of the polar night zone. Visit Rovaniemi describes late December as the time when the sun doesn’t rise above the horizon. The long polar night is further north: 51 days in Finland’s northernmost corner, according to FMI.

Is it completely dark all day during kaamos?

No. Sunlight still reaches the upper atmosphere, so there is blue twilight around midday, and snow and moonlight brighten the landscape (thisisFINLAND).

What causes the polar night?

Earth’s tilted axis. In December the Northern Hemisphere is tilted away from the Sun, so near and beyond the Arctic Circle the sun stays at or below the horizon (NASA).

Where in Finland is the polar night longest?

In the far north. FMI gives 51 days for the northernmost corner, and thisisFINLAND says it lasts almost two months in Utsjoki.

Does the polar night mean more Northern Lights?

Not more auroras, but more dark hours to see them. The aurora depends on solar activity and clear skies. FMI notes that displays typically peak around midnight.

Which StayLapland tour suits the dark weeks best?

We usually suggest the Northern Lights Tour in Atmospheric Cottage, from 109 € for 3 hours, because it combines time outdoors with a warm cottage. If a guaranteed sighting matters most, choose one of our guaranteed hunting tours.

Ready to book?

You may also like

• Northern Lights Tour At The Campfire — from 99 €, 3 hours
• Professional Guaranteed Northern Lights Hunting Tour from Rovaniemi by Bus — from 109 €, Total duration of tour is usually 4-5 hours depends on conditions of the day
• Professional Small Group Northern Lights Hunting Tour from Rovaniemi – Guaranteed — from 199 €, Total duration of tour is usually 4-10 hours depends on conditions of the day

Sources

• Finnish Meteorological Institute: Seasons in Finland
• Finnish Meteorological Institute: Auroras in Finland
• NASA Space Place: What Causes the Seasons?
• thisisFINLAND: When the sun doesn’t rise in northern Finland
• Visit Rovaniemi: Polar Night
• Visit Finland: Epic photos of Finnish winter darkness