A common myth says the aurora only appears when it's very cold. The temperature on the ground has nothing to do with whether the aurora forms — but there's a grain of truth to why cold nights feel luckier.
Here's the real relationship.
Temperature doesn't cause the aurora
The aurora happens 100+ km up and is driven entirely by solar activity, not by ground temperature. It can appear at −25°C or at +5°C in early autumn — the Sun doesn't care how cold your toes are.
Why cold nights seem better
Here's the truth behind the myth: cold, clear air is usually cloud-free air. In deep winter, the coldest nights often coincide with high pressure and crystal-clear skies — perfect for seeing an aurora that would be hidden on a milder, cloudier night.
Autumn aurora in mild weather
In September, Ruka can be a mild 0–8°C and still deliver superb aurora, thanks to the autumn equinox. Warm doesn't mean no aurora.
What actually matters
Darkness, clear skies and geomagnetic activity — not temperature. Dress for the cold and focus on the forecast. Our tours chase clear skies whatever the thermometer says.