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Weather & Climate in Cromwell, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Cromwell experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 21°F in January while summers reach 74°F in July. The area gets 275 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 37.9 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,279 feet.
Temperature
21°F Jan (-6°C)
74°F Jul (23°C)
| Annual Average | 48.8°F |
| 10% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 74°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 1,279 ft (390 m) |
| Area | 0.3 sq mi (0.8 km²) |
| Population Density | 290/sq mi |
| Coordinates | 41.0405°N, 94.4618°W |
| Timezone | America/Chicago |
| County | Union County County |
| Nearest Airport | Des Moines International (DSM) 51 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 49.5 / 100 |
| Social Vulnerability | 74.2 / 100 |
| Community Resilience | 76.9 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
4 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.6.
| Dec 17, 2009 | 2 km NW of Auburn, Nebraska | M3.6 | 138 km | 5 km |
| Jul 16, 2004 | 6 km SSE of Riverton, Iowa | M3.5 | 102 km | 5 km |
| Feb 11, 1995 | 6 km E of Clearmont, Missouri | M3.1 | 73 km | 5 km |
| Mar 31, 1993 | 2 km SE of Nemaha, Nebraska | M2.9 | 128 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
621 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 21 fatalities, 247 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 27, 1953 | EF5 | 50 km | 0.1 mi | 1 |
| May 21, 2024 | EF4 | 42 km | 40.7 mi | 5 |
| Mar 5, 2022 | EF4 | 31 km | 70.6 mi | 6 |
| Apr 8, 1999 | EF4 | 12 km | 56.0 mi | 0 |
| Apr 8, 1999 | EF4 | 43 km | 49.0 mi | 0 |
| May 27, 1995 | EF4 | 5 km | 57.0 mi | 0 |
| May 27, 1995 | EF4 | 84 km | 30.0 mi | 0 |
| May 24, 1989 | EF4 | 23 km | 49.0 mi | 0 |
| Jun 7, 1984 | EF4 | 78 km | 134.0 mi | 3 |
| Jun 2, 1980 | EF4 | 65 km | 31.2 mi | 0 |
| Mar 29, 1979 | EF4 | 85 km | 18.8 mi | 0 |
| Jun 22, 1964 | EF4 | 91 km | 11.9 mi | 0 |
| Apr 12, 1964 | EF4 | 77 km | 13.1 mi | 1 |
| May 10, 1959 | EF4 | 53 km | 41.1 mi | 0 |
| Apr 5, 1954 | EF4 | 95 km | 6.3 mi | 0 |
| May 10, 1953 | EF4 | 97 km | 6.4 mi | 0 |
| May 21, 2024 | EF3 | 65 km | 33.9 mi | 0 |
| Mar 5, 2022 | EF3 | 91 km | 11.3 mi | 1 |
| Aug 20, 2019 | EF3 | 82 km | 5.4 mi | 0 |
| Apr 11, 2001 | EF3 | 74 km | 76.5 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: UNNAMED (4,195 acres, 2005).
| Year | Name | Acres Burned | Distance |
| 2005 | UNNAMED | 4,195 | 74 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 0.9 in | Coldest, Driest |
| February | 27°F (-3°C) | 1.0 in | |
| March | 38°F (3°C) | 2.3 in | |
| April | 50°F (10°C) | 3.4 in | |
| May | 61°F (16°C) | 4.4 in | Wettest |
| June | 71°F (22°C) | 4.4 in | |
| July | 74°F (23°C) | 4.4 in | Warmest |
| August | 73°F (23°C) | 4.0 in | |
| September | 64°F (18°C) | 4.3 in | |
| October | 53°F (11°C) | 2.6 in | |
| November | 37°F (3°C) | 1.9 in | |
| December | 25°F (-4°C) | 1.1 in |
Cromwell has a seasonal temperature swing of 54°F / from 21°F in January to 74°F in July. Total annual precipitation is 34.8 inches, with May being the wettest month (4.4") and January the driest (0.9").