All Countries
Weather & Climate in Decatur, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Decatur experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 24°F in January while summers reach 76°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 37.4 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,132 feet.
Temperature
24°F Jan (-4°C)
76°F Jul (24°C)
| Annual Average | 51.6°F |
| 4% below US avg | |
| January Average | 24°F (-4°C) |
| July Average | 76°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 1,132 ft (345 m) |
| Area | 0.4 sq mi (1.0 km²) |
| Population Density | 429/sq mi |
| Coordinates | 40.7427°N, 93.8328°W |
| Timezone | America/Chicago |
| County | Decatur County County |
| Nearest Airport | Des Moines International (DSM) 53 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 23.6 / 100 |
| Social Vulnerability | 43.0 / 100 |
| Community Resilience | 41.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Very Low |
| Lightning | Very Low |
| Ice Storm | Very Low |
| Drought | Relatively High |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.5.
| Jul 16, 2004 | 6 km SSE of Riverton, Iowa | M3.5 | 145 km | 5 km |
| Feb 11, 1995 | 6 km E of Clearmont, Missouri | M3.1 | 98 km | 5 km |
| Jul 15, 2025 | 3 km W of Hale, Missouri | M2.5 | 133 km | 8 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
525 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 19 fatalities, 215 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 21, 2024 | EF4 | 94 km | 40.7 mi | 5 |
| Mar 5, 2022 | EF4 | 63 km | 70.6 mi | 6 |
| Apr 8, 1999 | EF4 | 91 km | 49.0 mi | 0 |
| Apr 8, 1999 | EF4 | 52 km | 56.0 mi | 0 |
| May 27, 1995 | EF4 | 61 km | 57.0 mi | 0 |
| May 24, 1989 | EF4 | 79 km | 49.0 mi | 0 |
| Jun 7, 1984 | EF4 | 40 km | 134.0 mi | 3 |
| Jun 2, 1980 | EF4 | 16 km | 31.2 mi | 0 |
| Apr 21, 1973 | EF4 | 52 km | 14.6 mi | 0 |
| May 20, 1959 | EF4 | 58 km | 17.2 mi | 0 |
| May 10, 1953 | EF4 | 45 km | 6.4 mi | 0 |
| Mar 5, 2022 | EF3 | 44 km | 11.3 mi | 1 |
| Aug 20, 2019 | EF3 | 63 km | 5.4 mi | 0 |
| Jun 22, 2015 | EF3 | 76 km | 11.1 mi | 0 |
| Apr 11, 2001 | EF3 | 61 km | 76.5 mi | 0 |
| Apr 8, 1999 | EF3 | 45 km | 39.0 mi | 0 |
| May 27, 1995 | EF3 | 24 km | 30.4 mi | 0 |
| Apr 14, 1994 | EF3 | 94 km | 14.0 mi | 0 |
| Mar 29, 1979 | EF3 | 96 km | 29.6 mi | 0 |
| Mar 29, 1979 | EF3 | 46 km | 57.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-4°C) | 0.9 in | Coldest, Driest |
| February | 28°F (-2°C) | 1.0 in | |
| March | 39°F (4°C) | 2.3 in | |
| April | 51°F (11°C) | 3.5 in | |
| May | 61°F (16°C) | 4.4 in | Wettest |
| June | 71°F (21°C) | 4.3 in | |
| July | 76°F (24°C) | 4.3 in | Warmest |
| August | 73°F (23°C) | 4.3 in | |
| September | 65°F (18°C) | 4.3 in | |
| October | 53°F (12°C) | 3.0 in | |
| November | 39°F (4°C) | 2.1 in | |
| December | 27°F (-3°C) | 1.3 in |
Decatur has a seasonal temperature swing of 52°F / from 24°F in January to 76°F in July. Total annual precipitation is 35.8 inches, with May being the wettest month (4.4") and January the driest (0.9").