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Weather & Climate in Knoxville, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Knoxville experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 21°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 37.5 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 911 feet.
Temperature
21°F Jan (-6°C)
75°F Jul (24°C)
| Annual Average | 49.9°F |
| 8% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 911 ft (278 m) |
| Area | 4.6 sq mi (12.0 km²) |
| Population Density | 1,622/sq mi |
| Coordinates | 41.3185°N, 93.1026°W |
| Timezone | America/Chicago |
| County | Marion County County |
| Nearest Airport | Des Moines International (DSM) 33 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 34.4 / 100 |
| Social Vulnerability | 13.4 / 100 |
| Community Resilience | 96.8 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively 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
593 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 20 fatalities, 304 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 13, 1976 | EF5 | 93 km | 21.3 mi | 0 |
| Mar 31, 2023 | EF4 | 90 km | 19.9 mi | 0 |
| Mar 5, 2022 | EF4 | 92 km | 70.6 mi | 6 |
| Sep 28, 1986 | EF4 | 63 km | 20.0 mi | 0 |
| Aug 12, 1974 | EF4 | 91 km | 2.0 mi | 0 |
| Jun 18, 1974 | EF4 | 63 km | 15.3 mi | 2 |
| May 20, 1959 | EF4 | 69 km | 17.2 mi | 0 |
| May 10, 1953 | EF4 | 53 km | 6.4 mi | 0 |
| Mar 31, 2023 | EF3 | 70 km | 26.1 mi | 0 |
| Mar 5, 2022 | EF3 | 48 km | 11.3 mi | 1 |
| Aug 20, 2019 | EF3 | 36 km | 5.4 mi | 0 |
| Jul 19, 2018 | EF3 | 21 km | 9.2 mi | 0 |
| Jul 19, 2018 | EF3 | 85 km | 8.4 mi | 0 |
| Jun 22, 2015 | EF3 | 17 km | 11.1 mi | 0 |
| Apr 8, 1999 | EF3 | 45 km | 39.0 mi | 0 |
| Apr 8, 1999 | EF3 | 85 km | 16.0 mi | 0 |
| Mar 22, 1991 | EF3 | 78 km | 43.0 mi | 0 |
| Mar 13, 1990 | EF3 | 81 km | 9.0 mi | 0 |
| Sep 16, 1978 | EF3 | 73 km | 31.8 mi | 6 |
| May 4, 1977 | EF3 | 94 km | 17.8 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
4 wildfires (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 | 33 km |
| 2009 | UNNAMED | 939 | 93 km |
| 2010 | FOLEY | 786 | 94 km |
| 2011 | IRCP WUI ROFAE #2 FY11 | 510 | 91 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 2.5 in | Coldest, Driest |
| February | 27°F (-3°C) | 2.5 in | |
| March | 39°F (4°C) | 3.7 in | |
| April | 51°F (10°C) | 3.6 in | |
| May | 62°F (17°C) | 4.2 in | |
| June | 71°F (22°C) | 4.3 in | |
| July | 75°F (24°C) | 4.5 in | Warmest, Wettest |
| August | 73°F (23°C) | 3.6 in | |
| September | 65°F (18°C) | 3.7 in | |
| October | 53°F (12°C) | 2.8 in | |
| November | 39°F (4°C) | 3.1 in | |
| December | 26°F (-3°C) | 2.8 in |
Knoxville has a seasonal temperature swing of 54°F / from 21°F in January to 75°F in July. Total annual precipitation is 41.3 inches, with July being the wettest month (4.5") and January the driest (2.5").