They're two different things that people often mix up. The polar night (kaamos) is a period of extended winter darkness near the poles; the Northern Lights (aurora) are the glowing light phenomenon you can see because of that darkness. One is a season; the other is a sight.
Here's how they relate — and what actually happens in Ruka.
What is the polar night?
The polar night, or kaamos in Finnish, is the stretch of winter when the sun stays below the horizon. The further north you go, the longer it lasts — weeks or months at the highest latitudes. It's the reason the far north has such long, dark nights in mid-winter.
What are the Northern Lights?
The aurora is caused by solar particles hitting the upper atmosphere — see what are the Northern Lights. It happens year-round, but you can only see it when the sky is dark. So the darkness of winter is what makes the aurora visible, not what causes it.
Does Ruka have true polar night?
Not quite. Ruka sits at about 66°N, just south of the Arctic Circle's true polar-night zone. Even around the December solstice it still gets a few hours of dim, blue-pink twilight around midday rather than 24-hour darkness. You get wonderfully long dark nights for aurora hunting without the sky being pitch black all day.
Darkness through the season
- September: ~10–13 hrs of darkness
- December–January: up to ~18 hrs (a few hours of midday twilight)
- March: ~11–13 hrs
More darkness means more hours the aurora can appear — see our best time guide.
Why it matters for your trip
You don't need true polar night to see the aurora — you need dark, clear skies and activity, all of which Ruka has in abundance. Book a guided hunt during the long-night months for the best experience.