Where in Illinois is best for the aurora?

By geomagnetic latitude, Waukegan at 51.2°. No town sits at 60 degrees or more, so every town needs some activity.

Which town in Illinois has the longest December night?

Waukegan, with 13.8 hours of civil night on December 15.

Which town in Illinois has the clearest dark season?

Wheaton, with 59% mean cloud amount in the months with at least 4 hours of civil night (NASA POWER, 2001 to 2020).

What is the best month for aurora in Illinois?

September for 11 of 11 towns, by civil night times the clear share of the sky. Each town page gives its own month.

Illinois aurora towns ranked: 23 places

Where the towns sit

60° geomagnetic or more, no storm needed55° to 60°, G1 or lessbelow 55°, storm needed

The widest gap in the dipole ranking falls between Waukegan and Rockford, 0.2 degrees. 10 neighbouring pairs sit within 0.5 degrees of each other, close enough that the order between them means little.

Of the 11 indexed towns in Illinois, 11 sit below 55 degrees and need a G2 or stronger storm by NOAA's typical latitudes.

Ranked by geomagnetic latitude

Dipole latitude, highest first
Rank	Town	Value
1	Waukegan	51.2°
2	Rockford	51.0°
3	Arlington Heights	50.9°
4	Evanston	50.9°
5	Elgin, Illinois	50.9°
6	Chicago	50.7°
7	Wheaton	50.7°
8	Aurora, Illinois	50.6°
9	Bolingbrook	50.5°
10	Orland Park	50.5°
11	Joliet	50.4°

Ranked by December darkness

On December 15 the median town gets 13.7 hours of civil night, against 13.8 nationally. Waukegan has the most at 13.8 hours and Arlington Heights the least at 13.7. Every town keeps some civil darkness through the June solstice.

Civil night on December 15, longest first
Rank	Town	Value
1	Waukegan	13.8 h
2	Rockford	13.8 h
3	Arlington Heights	13.7 h
4	Evanston	13.7 h
5	Elgin, Illinois	13.7 h
6	Chicago	13.7 h
7	Wheaton	13.7 h
8	Aurora, Illinois	13.7 h
9	Bolingbrook	13.7 h
10	Orland Park	13.7 h
11	Joliet	13.7 h

Ranked by clear dark season

NASA POWER's 2001 to 2020 climatology puts median cloud amount in the dark months at 60%, against 61% nationally. Wheaton is clearest at 59% and Evanston cloudiest at 74%. These are all-hours averages for 1 degree cells, not forecasts.

Mean cloud amount in months with 4 hours or more of civil night, clearest first
Rank	Town	Value
1	Wheaton	59%
2	Aurora, Illinois	59%
3	Bolingbrook	59%
4	Joliet	59%
5	Rockford	59%
6	Elgin, Illinois	60%
7	Chicago	61%
8	Orland Park	61%
9	Waukegan	74%
10	Arlington Heights	74%
11	Evanston	74%

Multiplying civil night by the clear share of the sky, September comes out best for 11 of the 11 towns. SWPC notes a tendency toward larger storms near the equinoxes, which this score does not include.

Every town

23 towns in Illinois
Town	Dipole	Storm needed	Dec 15 night	Dark-month cloud	Best month
Waukegan	51.2°	G2 or more	13.8 h	74%	Sep
Rockford	51.0°	G2 or more	13.8 h	59%	Sep
Palatine *	50.9°	G2 or more	13.7 h	60%	Sep
Arlington Heights	50.9°	G2 or more	13.7 h	74%	Sep
Mount Prospect *	50.9°	G2 or more	13.7 h	74%	Sep
Evanston	50.9°	G2 or more	13.7 h	74%	Sep
Skokie *	50.9°	G2 or more	13.7 h	74%	Sep
Des Plaines *	50.9°	G2 or more	13.7 h	74%	Sep
Hoffman Estates *	50.9°	G2 or more	13.7 h	60%	Sep
Schaumburg *	50.9°	G2 or more	13.7 h	60%	Sep
Elgin, Illinois	50.9°	G2 or more	13.7 h	60%	Sep
Oak Park *	50.7°	G2 or more	13.7 h	61%	Sep
Chicago	50.7°	G2 or more	13.7 h	61%	Sep
Wheaton	50.7°	G2 or more	13.7 h	59%	Sep
Berwyn *	50.7°	G2 or more	13.7 h	61%	Sep
Cicero *	50.7°	G2 or more	13.7 h	61%	Sep
Naperville *	50.6°	G2 or more	13.7 h	59%	Sep
Aurora, Illinois	50.6°	G2 or more	13.7 h	59%	Sep
Oak Lawn *	50.6°	G2 or more	13.7 h	61%	Sep
Bolingbrook	50.5°	G2 or more	13.7 h	59%	Sep
Orland Park	50.5°	G2 or more	13.7 h	61%	Sep
Tinley Park *	50.4°	G2 or more	13.7 h	61%	Sep
Joliet	50.4°	G2 or more	13.7 h	59%	Sep

* Within 15 km of a larger town with the same rounded figures; its page points to that town. Cloud: NASA POWER mean for months with at least 4 hours of civil night.

Questions

Where in Illinois is best for the aurora?: By geomagnetic latitude, Waukegan at 51.2°. No town sits at 60 degrees or more, so every town needs some activity.
Which town in Illinois has the longest December night?: Waukegan, with 13.8 hours of civil night on December 15.
Which town in Illinois has the clearest dark season?: Wheaton, with 59% mean cloud amount in the months with at least 4 hours of civil night (NASA POWER, 2001 to 2020).
What is the best month for aurora in Illinois?: September for 11 of 11 towns, by civil night times the clear share of the sky. Each town page gives its own month.

Top towns in Illinois

Other regions of United States

More

Sources and verification

GeoNames dump (CC BY 4.0)https://download.geonames.org/export/dump/
IGRF-14, NOAA NCEIhttps://www.ngdc.noaa.gov/IAGA/vmod/coeffs/igrf14coeffs.txt
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/

Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.