Iowa weather in September: Statewide normals and every place, NOAA 1991-2020
In September, Iowa's statewide normal high is 75°F and normal low 52°F; normal highs run from 71°F in Northwood to 79°F in Glenwood (NOAA 1991-2020 normals).
- Statewide normal high
- 75°FSeptember, 1991-2020
- Statewide normal low
- 52°FSeptember, 1991-2020
- Statewide normal precipitation
- 3.48 inSeptember
- Warmest place
- 79°Fnormal high, Glenwood
- Coolest place
- 71°Fnormal high, Northwood
Where is Iowa warmest and wettest in September?
Glenwood has the warmest September afternoons (79°F) and Northwood the coolest (71°F). Little Sioux gets the most precipitation (5.05 in) and Pocahontas the least (2.60 in).
Statewide, September averaged 66.6°F in 2021, 65.1°F in 2022, 67.2°F in 2023, 66.7°F in 2024, 66.9°F in 2025, against a 1991-2020 normal of 63.7°F.
| Place | High | Low | Precip. | Snow |
|---|---|---|---|---|
| Des Moines | 77°F | 55°F | 3.18 | 0.0 |
| Cedar Rapids | 75°F | 52°F | 3.40 | – |
| Davenport | 76°F | 53°F | 3.47 | – |
| Sioux City | 77°F | 51°F | 2.84 | 0.0 |
| Ankeny | 77°F | 53°F | 3.62 | 0.0 |
| Iowa City | 78°F | 54°F | 3.24 | – |
| Ames | 76°F | 51°F | 3.31 | – |
| Waterloo | 77°F | 52°F | 3.14 | 0.0 |
| Dubuque | 73°F | 52°F | 3.82 | 0.0 |
| Marion | 77°F | 53°F | 3.96 | 0.0 |
| Marshalltown | 75°F | 51°F | 3.20 | – |
| Mason City | 74°F | 49°F | 3.45 | 0.0 |
| Ottumwa | 77°F | 53°F | 3.50 | 0.0 |
| Fort Dodge | 74°F | 51°F | 2.81 | 0.0 |
| Clinton | 76°F | 55°F | 3.69 | 0.0 |
| Burlington | 78°F | 56°F | 3.53 | – |
| Muscatine | 78°F | 54°F | 3.91 | 0.0 |
| Indianola | 78°F | 52°F | 3.86 | 0.0 |
| Newton | 76°F | 52°F | 3.59 | 0.0 |
| Boone | 76°F | 52°F | 3.32 | 0.0 |
| Storm Lake | 74°F | 53°F | 2.96 | – |
| Oskaloosa | 77°F | 53°F | 3.56 | – |
| Spencer | 76°F | 50°F | 3.21 | – |
| Le Mars | 76°F | 50°F | 3.14 | 0.0 |
| Carroll | 76°F | 52°F | 2.95 | – |
| Fort Madison | 77°F | 57°F | 3.51 | 0.0 |
| Fairfield | 76°F | 53°F | 3.58 | 0.0 |
| Grinnell | 75°F | 50°F | 3.71 | 0.0 |
| Keokuk | 77°F | 56°F | 3.42 | – |
| Sioux Center | 77°F | 51°F | 3.21 | 0.0 |
| Mount Pleasant | 77°F | 52°F | 4.13 | 0.0 |
| Denison | 75°F | 52°F | 3.27 | 0.0 |
| Perry | 77°F | 52°F | 3.44 | – |
| Webster City | 75°F | 49°F | 3.36 | 0.0 |
| Decorah | 76°F | 52°F | 3.60 | 0.0 |
| Knoxville | 76°F | 54°F | 3.66 | – |
| Creston | 76°F | 52°F | 3.70 | – |
| Washington | 77°F | 51°F | 3.60 | 0.0 |
| Charles City | 73°F | 51°F | 3.82 | 0.0 |
| Atlantic | 78°F | 51°F | 3.35 | 0.0 |
| Independence | 75°F | 51°F | 3.53 | 0.0 |
| Maquoketa | 75°F | 52°F | 3.64 | 0.0 |
| Anamosa | 75°F | 50°F | 3.72 | – |
| Estherville | 73°F | 49°F | 3.14 | – |
| Oelwein | 74°F | 51°F | – | – |
| Osceola | 78°F | 51°F | 3.85 | 0.0 |
| Sheldon | 74°F | 48°F | 3.39 | 0.0 |
| Spirit Lake | 73°F | 52°F | 3.03 | 0.0 |
| Winterset | 76°F | 51°F | 3.60 | 0.0 |
| Red Oak | 78°F | 53°F | 3.58 | 0.0 |
| Centerville | 76°F | 52°F | 3.85 | 0.0 |
| Algona | 75°F | 50°F | 3.27 | – |
| Clarinda | 78°F | 52°F | 3.30 | 0.0 |
| Manchester | 74°F | 49°F | 3.84 | 0.0 |
| Glenwood | 79°F | 53°F | 3.32 | 0.0 |
| Cherokee | 75°F | 50°F | 3.29 | 0.0 |
| Iowa Falls | 75°F | 51°F | 3.49 | 0.0 |
| Vinton | 74°F | 50°F | 3.68 | 0.0 |
| Harlan | 79°F | 52°F | 4.00 | 0.0 |
| Shenandoah | 79°F | 55°F | 3.02 | 0.0 |
| Le Claire | 77°F | 56°F | 3.35 | – |
| Humboldt | 73°F | 51°F | 3.33 | – |
| Hampton | 75°F | 50°F | 3.30 | – |
| Chariton | 76°F | 50°F | 3.71 | 0.0 |
| Forest City | 73°F | 50°F | 3.46 | – |
| Jefferson | 76°F | 51°F | 3.13 | 0.0 |
| Cresco | 74°F | 48°F | 3.76 | 0.0 |
| Waukon | 72°F | 51°F | 3.92 | – |
| Emmetsburg | 76°F | 51°F | 3.40 | 0.0 |
| Albia | 76°F | 54°F | 3.57 | 0.0 |
| Osage | 73°F | 50°F | 3.51 | 0.0 |
| New Hampton | 73°F | 49°F | 3.83 | 0.0 |
| Williamsburg | 76°F | 51°F | 3.80 | 0.0 |
| Milford | 74°F | 52°F | 3.21 | 0.0 |
| Tipton | 77°F | 53°F | 3.46 | – |
| Grundy Center | 75°F | 51°F | 3.28 | 0.0 |
| Onawa | 78°F | 50°F | 2.97 | 0.0 |
| Sibley | 74°F | 49°F | 3.25 | 0.0 |
| Bloomfield | 77°F | 55°F | 3.95 | 0.0 |
| Clarion | 76°F | 51°F | 3.13 | 0.0 |
| Rock Rapids | 75°F | 50°F | 3.24 | 0.0 |
| Hawarden | 76°F | 50°F | 3.25 | 0.0 |
| Eldora | 76°F | 51°F | 3.56 | 0.0 |
| Postville | 74°F | 49°F | 3.96 | 0.0 |
| Cascade | 75°F | 51°F | 3.79 | 0.0 |
| Toledo | 75°F | 51°F | 3.48 | 0.0 |
| Belle Plaine | 76°F | 51°F | 3.55 | 0.0 |
| Bellevue | 76°F | 52°F | 3.65 | 0.0 |
| Rockwell City | 75°F | 51°F | 2.95 | 0.0 |
| Lamoni | 77°F | 55°F | 3.71 | – |
| Northwood | 71°F | 48°F | 3.32 | 0.0 |
| Audubon | 75°F | 50°F | 3.52 | – |
| Britt | 73°F | 50°F | 3.21 | – |
| Sac City | 75°F | 50°F | 2.85 | 0.0 |
| Greenfield | 76°F | 53°F | 3.91 | 0.0 |
| Ida Grove | 75°F | 52°F | – | – |
| Sigourney | 76°F | 52°F | 3.47 | – |
| Pocahontas | 76°F | 50°F | 2.60 | 0.0 |
| Guttenberg | 75°F | 54°F | 3.75 | 0.0 |
| Columbus Junction | 76°F | 52°F | 3.75 | 0.0 |
| Leon | 76°F | 50°F | 4.17 | 0.0 |
| Mount Ayr | 76°F | 53°F | 3.71 | 0.0 |
| Guthrie Center | 77°F | 50°F | 3.61 | – |
| Oakland | 77°F | 53°F | 3.62 | 0.0 |
| Corning | 76°F | 52°F | 3.50 | 0.0 |
| Holstein | 73°F | 52°F | 3.08 | 0.0 |
| Bedford | 77°F | 54°F | 3.38 | – |
| Sanborn | 74°F | 50°F | 3.31 | 0.0 |
| Logan | 78°F | 51°F | 3.54 | 0.0 |
| Tripoli | 75°F | 50°F | 3.75 | – |
| Fayette | 74°F | 48°F | 3.87 | 0.0 |
| Elkader | 74°F | 49°F | 3.63 | 0.0 |
| Lake Park | 76°F | 51°F | 2.91 | 0.0 |
| Mapleton | 75°F | 50°F | 3.12 | 0.0 |
| Sidney | 78°F | 54°F | 3.10 | 0.0 |
| Keosauqua | 78°F | 53°F | 3.69 | 0.0 |
| Allison | 74°F | 51°F | 3.37 | – |
| Primghar | 76°F | 53°F | 3.30 | 0.0 |
| Donnellson | 79°F | 54°F | 3.92 | 0.0 |
| Colo | 75°F | 52°F | 3.37 | 0.0 |
| Lowden | 77°F | 51°F | 3.55 | 0.0 |
| Dakota City | 76°F | 51°F | 3.24 | – |
| Sioux Rapids | 74°F | 51°F | 3.39 | 0.0 |
| Coggon | 75°F | 49°F | 3.94 | – |
| Battle Creek | 76°F | 50°F | 3.16 | – |
| Swea City | 73°F | 48°F | 3.21 | 0.0 |
| Allerton | 76°F | 54°F | 4.20 | – |
| Little Sioux | 77°F | 50°F | 5.05 | 0.0 |
| Castana | 75°F | 53°F | 3.05 | 0.0 |
| Stanley | 74°F | 48°F | 3.71 | – |
| Rathbun | 77°F | 54°F | 3.81 | – |
| Beaconsfield | 76°F | 53°F | 4.11 | 0.0 |
| Des Moines Weather Office-Johnston | 76°F | 55°F | 3.40 | 0.0 |
| Sioux City Ang | 77°F | 51°F | 2.99 | – |
Source: NOAA NCEI nClimDiv statewide normals; NOAA NCEI 1991-2020 monthly normals for each station.