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Weather & Climate in Derby, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Derby experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 22°F in January while summers reach 75°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 40.4 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,088 feet.
Temperature
22°F Jan (-5°C)
75°F Jul (24°C)
| Annual Average | 49.9°F |
| 8% below US avg | |
| January Average | 22°F (-5°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 1,088 ft (332 m) |
| Area | 0.3 sq mi (0.7 km²) |
| Population Density | 408/sq mi |
| Coordinates | 40.9303°N, 93.4565°W |
| Timezone | America/Chicago |
| County | Wayne County County |
| Nearest Airport | Des Moines International (DSM) 41 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 22.0 / 100 |
| Social Vulnerability | 73.9 / 100 |
| Community Resilience | 46.2 / 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 | Relatively Low |
| Drought | Relatively High |
| Cold Wave | Relatively Low |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
2 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.1.
| Feb 11, 1995 | 6 km E of Clearmont, Missouri | M3.1 | 135 km | 5 km |
| Jul 15, 2025 | 3 km W of Hale, Missouri | M2.5 | 148 km | 8 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
556 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 18 fatalities, 246 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 5, 2022 | EF4 | 71 km | 70.6 mi | 6 |
| Apr 8, 1999 | EF4 | 73 km | 56.0 mi | 0 |
| May 27, 1995 | EF4 | 82 km | 57.0 mi | 0 |
| Sep 28, 1986 | EF4 | 92 km | 20.0 mi | 0 |
| Jun 7, 1984 | EF4 | 75 km | 134.0 mi | 3 |
| Jun 2, 1980 | EF4 | 52 km | 31.2 mi | 0 |
| Jun 18, 1974 | EF4 | 90 km | 15.3 mi | 2 |
| Apr 21, 1973 | EF4 | 67 km | 14.6 mi | 0 |
| Jan 24, 1967 | EF4 | 98 km | 25.7 mi | 0 |
| May 20, 1959 | EF4 | 36 km | 17.2 mi | 0 |
| May 10, 1953 | EF4 | 13 km | 6.4 mi | 0 |
| Mar 31, 2023 | EF3 | 95 km | 26.1 mi | 0 |
| Mar 5, 2022 | EF3 | 6 km | 11.3 mi | 1 |
| Aug 20, 2019 | EF3 | 37 km | 5.4 mi | 0 |
| Jul 19, 2018 | EF3 | 73 km | 9.2 mi | 0 |
| Jun 22, 2015 | EF3 | 39 km | 11.1 mi | 0 |
| Apr 11, 2001 | EF3 | 98 km | 76.5 mi | 0 |
| Apr 8, 1999 | EF3 | 16 km | 39.0 mi | 0 |
| Apr 8, 1999 | EF3 | 90 km | 16.0 mi | 0 |
| May 27, 1995 | EF3 | 61 km | 30.4 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: NEAL SMITH WUI 2016 1 (1,050 acres, 2016).
| Year | Name | Acres Burned | Distance |
| 2016 | NEAL SMITH WUI 2016 1 | 1,050 | 74 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 22°F (-5°C) | 1.0 in | Coldest, Driest |
| February | 27°F (-3°C) | 1.1 in | |
| March | 39°F (4°C) | 2.4 in | |
| April | 51°F (10°C) | 3.5 in | |
| May | 61°F (16°C) | 4.1 in | |
| June | 71°F (21°C) | 4.5 in | Wettest |
| July | 75°F (24°C) | 4.5 in | Warmest |
| August | 73°F (23°C) | 4.1 in | |
| September | 65°F (18°C) | 4.5 in | |
| October | 53°F (12°C) | 3.0 in | |
| November | 38°F (4°C) | 2.2 in | |
| December | 26°F (-3°C) | 1.4 in |
Derby has a seasonal temperature swing of 52°F / from 22°F in January to 75°F in July. Total annual precipitation is 36.2 inches, with June being the wettest month (4.5") and January the driest (1.0").