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Weather & Climate in Delaware, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Delaware experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 17°F in January while summers reach 72°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 38.6 inches. The area receives 34.7 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 1,051 feet.
Temperature
17°F Jan (-8°C)
72°F Jul (22°C)
| Annual Average | 46.3°F |
| 14% below US avg | |
| January Average | 17°F (-8°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 1,051 ft (320 m) |
| Area | 0.7 sq mi (1.9 km²) |
| Population Density | 173/sq mi |
| Coordinates | 42.4721°N, 91.3383°W |
| Timezone | America/Chicago |
| County | Delaware County County |
| Nearest Airport | Monticello Regional (MXO) 20 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 49.8 / 100 |
| Social Vulnerability | 32.6 / 100 |
| Community Resilience | 90.7 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tornado History
576 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 12 fatalities, 431 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 15, 1968 | EF5 | 53 km | 13.1 mi | 5 |
| Mar 13, 1990 | EF4 | 28 km | 19.0 mi | 0 |
| Aug 12, 1974 | EF4 | 18 km | 5.0 mi | 0 |
| Aug 26, 1965 | EF4 | 73 km | 4.7 mi | 1 |
| Apr 11, 1965 | EF4 | 77 km | 91.5 mi | 1 |
| Apr 30, 1954 | EF4 | 54 km | 80.4 mi | 0 |
| Aug 7, 2021 | EF3 | 89 km | 9.4 mi | 0 |
| May 25, 2008 | EF3 | 58 km | 32.0 mi | 0 |
| May 21, 2004 | EF3 | 61 km | 3.0 mi | 0 |
| May 11, 2000 | EF3 | 91 km | 18.6 mi | 1 |
| Jul 27, 1995 | EF3 | 31 km | 20.0 mi | 0 |
| Jun 19, 1993 | EF3 | 17 km | 9.0 mi | 0 |
| Jun 19, 1993 | EF3 | 54 km | 14.0 mi | 0 |
| Jul 13, 1992 | EF3 | 37 km | 5.0 mi | 0 |
| May 8, 1988 | EF3 | 93 km | 32.0 mi | 0 |
| May 8, 1988 | EF3 | 92 km | 16.0 mi | 0 |
| May 30, 1985 | EF3 | 45 km | 34.0 mi | 2 |
| Nov 9, 1975 | EF3 | 98 km | 39.4 mi | 0 |
| Jul 12, 1971 | EF3 | 24 km | 0.1 mi | 0 |
| Jun 24, 1971 | EF3 | 77 km | 0.1 mi | 1 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: ACE AUTO (676 acres, 2011).
| Year | Name | Acres Burned | Distance |
| 2011 | ACE AUTO | 676 | 96 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 17°F (-8°C) | 0.9 in | Coldest, Driest |
| February | 23°F (-5°C) | 1.1 in | |
| March | 35°F (2°C) | 2.2 in | |
| April | 48°F (9°C) | 3.3 in | |
| May | 60°F (16°C) | 4.0 in | |
| June | 69°F (21°C) | 4.5 in | |
| July | 72°F (22°C) | 4.2 in | Warmest |
| August | 70°F (21°C) | 4.6 in | Wettest |
| September | 62°F (17°C) | 4.0 in | |
| October | 51°F (10°C) | 2.6 in | |
| November | 35°F (2°C) | 2.1 in | |
| December | 22°F (-5°C) | 1.5 in |
Delaware has a seasonal temperature swing of 55°F / from 17°F in January to 72°F in July. Total annual precipitation is 35.0 inches, with August being the wettest month (4.6") and January the driest (0.9").