Aurora towns in Norway

Of the 32 indexed towns in Norway, 16 sit at 60 degrees geomagnetic or more, in or poleward of SWPC's 60 to 75 degree band, where no storm is needed; 16 sit between 55 and 60 degrees, where G1 (Kp 5) or less usually brings aurora into view.

On December 15 the median town gets 16.0 hours of civil night. Alta has the most at 19.4 hours and Arendal the least at 15.7. 15 of these towns lose civil darkness altogether around the June solstice; Alta goes longest, 112 nights.

NASA POWER's 2001 to 2020 climatology puts median cloud amount in the dark months at 77%. Gjøvik is clearest at 73% and Ålesund cloudiest at 83%. These are all-hours averages for 1 degree cells, not forecasts.

Multiplying civil night by the clear share of the sky, December comes out best for 17 of the 32 towns and January for 5. SWPC notes a tendency toward larger storms near the equinoxes, which this score does not include.

The towns fall in 15 first-level regions. Rogaland has 5, Østfold has 4, Vestfold has 4, Agder has 3. Regions with at least 5 indexed towns have their own page with three rankings.

• Rogaland5 towns
• Østfold4 towns
• Vestfold4 towns
• Agder3 towns
• Innlandet3 towns
• Møre og Romsdal3 towns
• Troms3 towns
• Trøndelag3 towns
• Vestland3 towns
• Akershus2 towns
• Buskerud2 towns
• Nordland2 towns
• Telemark2 towns
• Finnmark1 towns
• Oslo1 towns