Aurora towns in United States

Of the 136 indexed towns in United States, 4 sit at 60 degrees geomagnetic or more, in or poleward of SWPC's 60 to 75 degree band, where no storm is needed; 8 sit between 55 and 60 degrees, where G1 (Kp 5) or less usually brings aurora into view; 124 sit below 55 degrees and need a G2 or stronger storm by NOAA's typical latitudes.

On December 15 the median town gets 13.8 hours of civil night. Fairbanks has the most at 17.2 hours and Stamford the least at 13.6. 3 of these towns lose civil darkness altogether around the June solstice; Fairbanks goes longest, 77 nights.

NASA POWER's 2001 to 2020 climatology puts median cloud amount in the dark months at 61%. Casper is clearest at 56% and Syracuse cloudiest at 80%. These are all-hours averages for 1 degree cells, not forecasts.

Multiplying civil night by the clear share of the sky, September comes out best for 103 of the 136 towns and November for 20. SWPC notes a tendency toward larger storms near the equinoxes, which this score does not include.

The towns fall in 23 first-level regions. Michigan has 30, Massachusetts has 29, Washington has 26, Illinois has 23. Regions with at least 5 indexed towns have their own page with three rankings.

• Michigan30 towns
• Massachusetts29 towns
• Washington26 towns
• Illinois23 towns
• Minnesota23 towns
• Connecticut20 towns
• New York17 towns
• Wisconsin14 towns
• Iowa10 towns
• Ohio8 towns
• North Dakota7 towns
• Oregon7 towns
• New Jersey6 towns
• Alaska5 towns
• Indiana5 towns
• Rhode Island4 towns
• Montana3 towns
• New Hampshire2 towns
• Pennsylvania2 towns
• South Dakota2 towns
• Idaho1 towns
• Maine1 towns
• Wyoming1 towns