Polnatt is the Norwegian word for the polar night - the period in midwinter when the sun does not rise above the horizon for an extended stretch. The phenomenon is a direct consequence of Earth's axial tilt: at latitudes above the Arctic Circle (66.5°N), the sun fails to clear the horizon for one or more days centered on the December solstice. The further north you travel, the longer the period lasts. At Lofoten's southern edge (around 68°N), polar night is only a few days long and the sun still briefly appears low at noon for most of December. In Tromsø (69.6°N) and Senja (69.3°N), the polar night runs roughly from November 27 to January 15, a full seven weeks without a sunrise.
The polar night is not the same as full darkness. The midday hours give a long, deep blue twilight as the sun travels just below the horizon, producing what photographers call the blå time - the blue hour - that stretches for two to four hours each day depending on latitude. Reading by ambient light outdoors is possible at midday; full astronomical darkness arrives only in the late afternoon and lasts through the night. The visual character of the polar night is a slow gradient of blues, purples and reds rather than the hard black-and-white of a temperate winter night.
Cultural responses to the polar night vary across Arctic Norway. In Tromsø, the city compensates with strong public lighting, a long café-and-restaurant culture, and the well-established mørketidsfestivalen (dark time festival) in late January that marks the return of the sun. Smaller fishing communities along the Lofoten and Senja coasts run a more practical rhythm - working hours shifted to the twilight middle of the day, evening hours given over to indoor crafts and gatherings, the long winter treated as a different working season rather than a hardship.
For the visiting traveler, the polar night is the right context for an aurora trip rather than a complication of it. The darkness that defines the polnatt is the same darkness that makes the northern lights visible. The twilight middle of the day gives a few hours of usable outdoor time for non-aurora activities (sea-to-summit winter walks, sled-dog or reindeer experiences, the museums and food halls of Tromsø) without sacrificing the long nights of darkness that the aurora needs. The polar night is the season, not the obstacle.