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Weather & Climate in Grissom AFB, IN
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Grissom AFB experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 24°F in January while summers reach 72°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 41.1 inches. The area receives 24.6 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 793 feet.
Temperature
24°F Jan (-4°C)
72°F Jul (22°C)
| Annual Average | 50.1°F |
| 7% below US avg | |
| January Average | 24°F (-4°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 793 ft (242 m) |
| Area | 4.0 sq mi (10.4 km²) |
| Population Density | 721/sq mi |
| Coordinates | 40.6571°N, 86.1454°W |
| Timezone | America/Indiana/Indianapolis |
| County | Miami County County |
| Nearest Airport | Delaware County Regional (MIE) 49 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 52.8 / 100 |
| Social Vulnerability | 53.4 / 100 |
| Community Resilience | 54.8 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Very Low |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
9 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.8.
| Jun 17, 2021 | Illinois-Indiana border region | M3.8 | 134 km | 6 km |
| Sep 12, 2004 | 4 km NW of Manilla, Indiana | M3.8 | 124 km | 2 km |
| Dec 20, 1990 | 5 km S of Stilesville, Indiana | M3.7 | 126 km | 5 km |
| Apr 14, 2000 | 4 km NW of Heritage Lake, Indiana | M3.6 | 112 km | 5 km |
| Dec 17, 1990 | Illinois-Indiana border region | M3.2 | 100 km | 10 km |
| Jan 26, 2012 | 5 km NE of Topeka, Indiana | M3.0 | 116 km | 5 km |
| Apr 17, 1990 | 8 km NW of Fort Recovery, Ohio | M3.0 | 111 km | 5 km |
| Jun 12, 2015 | 6 km NW of Convoy, Ohio | M2.6 | 121 km | 5 km |
| Jan 30, 2004 | 2 km S of Rockford, Ohio | M2.5 | 126 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
612 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 126 fatalities, 2,210 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 11, 1998 | EF4 | 99 km | 13.2 mi | 0 |
| Apr 26, 1994 | EF4 | 71 km | 14.0 mi | 3 |
| Mar 20, 1976 | EF4 | 75 km | 16.7 mi | 0 |
| Apr 3, 1974 | EF4 | 85 km | 108.7 mi | 18 |
| May 14, 1972 | EF4 | 99 km | 30.0 mi | 0 |
| Apr 11, 1965 | EF4 | 35 km | 48.0 mi | 25 |
| Apr 11, 1965 | EF4 | 94 km | 45.7 mi | 28 |
| Apr 11, 1965 | EF4 | 96 km | 21.2 mi | 31 |
| Apr 11, 1965 | EF4 | 68 km | 21.8 mi | 0 |
| Apr 11, 1965 | EF4 | 66 km | 52.5 mi | 4 |
| Mar 6, 1956 | EF4 | 50 km | 1.9 mi | 1 |
| Mar 31, 2023 | EF3 | 51 km | 6.4 mi | 0 |
| May 27, 2019 | EF3 | 36 km | 13.7 mi | 0 |
| May 27, 2019 | EF3 | 64 km | 12.8 mi | 0 |
| Aug 24, 2016 | EF3 | 22 km | 8.6 mi | 0 |
| Nov 17, 2013 | EF3 | 68 km | 37.9 mi | 0 |
| Jun 5, 2010 | EF3 | 4 km | 7.5 mi | 0 |
| Oct 18, 2007 | EF3 | 72 km | 20.3 mi | 0 |
| May 30, 2004 | EF3 | 8 km | 4.5 mi | 0 |
| Jun 11, 1998 | EF3 | 29 km | 18.5 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
1 tsunami recorded within 500 km. Highest wave on record: 3.0 m (10 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1954 | MICHIGAN CITY, IN (LAKE MICHIGAN) | Avalanche | 3.0 m | 7 | 131 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-4°C) | 2.1 in | Coldest |
| February | 28°F (-2°C) | 2.0 in | Driest |
| March | 38°F (3°C) | 2.9 in | |
| April | 49°F (10°C) | 4.0 in | |
| May | 61°F (16°C) | 3.9 in | |
| June | 70°F (21°C) | 3.6 in | |
| July | 72°F (22°C) | 4.3 in | Warmest, Wettest |
| August | 71°F (22°C) | 3.6 in | |
| September | 65°F (18°C) | 3.0 in | |
| October | 53°F (12°C) | 2.6 in | |
| November | 41°F (5°C) | 3.0 in | |
| December | 29°F (-1°C) | 3.0 in |
Grissom AFB has a seasonal temperature swing of 48°F / from 24°F in January to 72°F in July. Total annual precipitation is 37.8 inches, with July being the wettest month (4.3") and February the driest (2.0").