In itself, of course, this is normal enough: it happens every summer as the sun returns after the long polar night.

His eyes were shiny and cold as the polar night.

That is the famous polar night, with 24 hours of darkness each day.

The period of polar night can trigger depression in some people.

The polar night is when it stays dark for more than twenty four hours.

A lot of times It will be a polar night for the winter and the opposite happens in the summer.

By then the polar night would have set in.

Said another way, during the winter the Sun does not rise above the horizon, it is the polar night.

All through the long polar night, expeditions would continue to leave the city for the south.

It was still in the polar night which ended at the start of spring, 23 May.