United States · 10 towns
Aurora towns in Iowa
Answer
Where the towns sit
The widest gap in the dipole ranking falls between Waterloo, Iowa and Sioux City, 0.3 degrees. 7 neighbouring pairs sit within 0.5 degrees of each other, close enough that the order between them means little.
Of the 8 indexed towns in Iowa, 8 sit below 55 degrees and need a G2 or stronger storm by NOAA's typical latitudes.
Ranked by geomagnetic latitude
| Rank | Town | Value |
|---|---|---|
| 1 | Dubuque | 51.2° |
| 2 | Waterloo, Iowa | 51.1° |
| 3 | Sioux City | 50.8° |
| 4 | Cedar Rapids | 50.6° |
| 5 | Ames | 50.5° |
| 6 | Iowa City | 50.3° |
| 7 | Davenport | 50.2° |
| 8 | Des Moines | 50.1° |
Ranked by December darkness
On December 15 the median town gets 13.7 hours of civil night, against 13.8 nationally. Dubuque has the most at 13.8 hours and Cedar Rapids the least at 13.7. Every town keeps some civil darkness through the June solstice.
| Rank | Town | Value |
|---|---|---|
| 1 | Dubuque | 13.8 h |
| 2 | Waterloo, Iowa | 13.8 h |
| 3 | Sioux City | 13.8 h |
| 4 | Cedar Rapids | 13.7 h |
| 5 | Ames | 13.7 h |
| 6 | Iowa City | 13.7 h |
| 7 | Davenport | 13.7 h |
| 8 | Des Moines | 13.7 h |
Ranked by clear dark season
NASA POWER's 2001 to 2020 climatology puts median cloud amount in the dark months at 58%, against 61% nationally. Sioux City is clearest at 57% and Dubuque cloudiest at 60%. These are all-hours averages for 1 degree cells, not forecasts.
| Rank | Town | Value |
|---|---|---|
| 1 | Sioux City | 57% |
| 2 | Des Moines | 57% |
| 3 | Ames | 58% |
| 4 | Iowa City | 58% |
| 5 | Davenport | 58% |
| 6 | Waterloo, Iowa | 59% |
| 7 | Cedar Rapids | 59% |
| 8 | Dubuque | 60% |
Multiplying civil night by the clear share of the sky, September comes out best for 7 of the 8 towns and November for 1. SWPC notes a tendency toward larger storms near the equinoxes, which this score does not include.
Every town
| Town | Dipole | Storm needed | Dec 15 night | Dark-month cloud | Best month |
|---|---|---|---|---|---|
| Dubuque | 51.2° | G2 or more | 13.8 h | 60% | Sep |
| Waterloo, Iowa | 51.1° | G2 or more | 13.8 h | 59% | Sep |
| Sioux City | 50.8° | G2 or more | 13.8 h | 57% | Nov |
| Cedar Rapids | 50.6° | G2 or more | 13.7 h | 59% | Sep |
| Ames | 50.5° | G2 or more | 13.7 h | 58% | Sep |
| Iowa City | 50.3° | G2 or more | 13.7 h | 58% | Sep |
| Ankeny * | 50.2° | G2 or more | 13.7 h | 57% | Sep |
| Davenport | 50.2° | G2 or more | 13.7 h | 58% | Sep |
| Des Moines | 50.1° | G2 or more | 13.7 h | 57% | Sep |
| West Des Moines * | 50.1° | G2 or more | 13.7 h | 57% | Sep |
Questions
- Where in Iowa is best for the aurora?
- By geomagnetic latitude, Dubuque at 51.2°. No town sits at 60 degrees or more, so every town needs some activity.
- Which town in Iowa has the longest December night?
- Dubuque, with 13.8 hours of civil night on December 15.
- Which town in Iowa has the clearest dark season?
- Sioux City, with 57% 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 Iowa?
- September for 7 of 8 towns, by civil night times the clear share of the sky. Each town page gives its own month.
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.