Average Rainfall for Iowa in September
The tables below give monthly averages for rainfall during September at cities, communities and other locations around Iowa.
Each place has a total for the amount of precipitation it usually receives this month. There is also a count of the number of days with wet weather, when precipitation amounts to 0.01 inches (0.25 millimetres) or more.
The rainfall totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.
You can jump to a separate table for each region of the state: Eastern, Central and Western Iowa.
Eastern Iowa
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 7 | Burlington | 3.9 | 99 |
| 9 | Cedar Rapids | 4.0 | 101 |
| 8 | Clinton | 3.7 | 94 |
| 9 | Cresco | 3.8 | 96 |
| 10 | Davenport | 3.5 | 88 |
| 9 | Decorah | 3.6 | 91 |
| 9 | Dubuque | 3.9 | 99 |
| 8 | Iowa City | 3.5 | 88 |
| 7 | Keokuk | 3.4 | 87 |
| 9 | Waterloo | 3.1 | 80 |
Central Iowa
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 9 | Ames | 3.5 | 88 |
| 8 | Des Moines | 3.2 | 81 |
| 8 | Fort Dodge | 2.8 | 71 |
| 9 | Marshalltown | 3.9 | 98 |
| 9 | Mason City | 3.5 | 88 |
| 8 | Ottumwa | 3.5 | 89 |
Western Iowa
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 9 | Carroll | 3.0 | 75 |
| 8 | Lake Park | 2.9 | 74 |
| 7 | Milford | 3.2 | 82 |
| 6 | Onawa | 3.0 | 75 |
| 7 | Shenandoah | 3.0 | 77 |
| 8 | Sioux City | 2.8 | 72 |
| 6 | Spirit Lake | 3.0 | 77 |
Reference
NOAA National Centers for Environmental Information (NCEI). Climate Normals.