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Weather & Climate in DeForest, WI
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
DeForest experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 18°F in January while summers reach 71°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 35.5 inches. The area receives 42.6 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 884 feet.
Temperature
18°F Jan (-8°C)
71°F Jul (22°C)
| Annual Average | 46.0°F |
| 15% below US avg | |
| January Average | 18°F (-8°C) |
| July Average | 71°F (22°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 884 ft (269 m) |
| Area | 7.5 sq mi (19.4 km²) |
| Population Density | 1,152/sq mi |
| Coordinates | 43.2273°N, 89.3457°W |
| Timezone | America/Chicago |
| County | Dane County County |
| Nearest Airport | Dane County Regional/Truax Field (MSN) 6 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 38.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 93.9 / 100 |
| Social Vulnerability | 15.9 / 100 |
| Community Resilience | 97.8 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Relatively High |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively High |
| Ice Storm | Relatively High |
| Drought | Relatively Low |
| Cold Wave | Very High |
| Landslide | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1 earthquake (M2.5+) recorded within 150 km since 1990. Strongest on record: M2.9.
| Mar 25, 2015 | 3 km WNW of Lake in the Hills, Illinois | M2.9 | 141 km | 6 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
562 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 34 fatalities, 732 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jul 18, 1996 | EF5 | 79 km | 13.3 mi | 0 |
| Jun 7, 1984 | EF5 | 59 km | 36.0 mi | 9 |
| Apr 27, 1984 | EF4 | 84 km | 6.5 mi | 1 |
| Jul 3, 1983 | EF4 | 70 km | 0.5 mi | 0 |
| Apr 4, 1981 | EF4 | 95 km | 1.8 mi | 3 |
| Apr 21, 1974 | EF4 | 72 km | 26.0 mi | 0 |
| Apr 19, 1957 | EF4 | 98 km | 21.1 mi | 1 |
| Apr 3, 1956 | EF4 | 84 km | 11.5 mi | 7 |
| Sep 26, 1951 | EF4 | 28 km | 9.0 mi | 1 |
| Jun 16, 2014 | EF3 | 30 km | 1.0 mi | 0 |
| Aug 18, 2005 | EF3 | 35 km | 18.6 mi | 1 |
| Jun 23, 2004 | EF3 | 59 km | 7.6 mi | 1 |
| Jun 23, 2004 | EF3 | 60 km | 33.3 mi | 0 |
| Aug 29, 1992 | EF3 | 95 km | 28.0 mi | 1 |
| Jun 17, 1992 | EF3 | 41 km | 16.0 mi | 0 |
| Jun 8, 1984 | EF3 | 27 km | 29.0 mi | 0 |
| Jun 5, 1980 | EF3 | 48 km | 10.7 mi | 0 |
| Apr 7, 1980 | EF3 | 41 km | 1.2 mi | 0 |
| Jun 5, 1977 | EF3 | 83 km | 69.5 mi | 0 |
| Jun 4, 1975 | EF3 | 9 km | 2.3 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
10 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (1,524 acres, 2006).
| Year | Name | Acres Burned | Distance |
| 2006 | UNNAMED | 1,524 | 67 km |
| 2010 | RX BURN | 1,236 | 68 km |
| 1994 | SOMMERS | 938 | 66 km |
| 1988 | PEACHY RD | 812 | 64 km |
| 2018 | 2018 BADGER RX BURNS | 659 | 37 km |
| 2019 | 2019 BADGER RX BURNS | 627 | 36 km |
| 2006 | UNNAMED | 612 | 66 km |
| 2007 | TOWER RD 2 | 592 | 64 km |
| 2024 | RX-HWY Y - SOUTH | 553 | 57 km |
| 2009 | COLD SPRINGS | 552 | 66 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 18°F (-8°C) | 1.2 in | Coldest |
| February | 21°F (-6°C) | 1.1 in | Driest |
| March | 33°F (0°C) | 2.2 in | |
| April | 45°F (7°C) | 3.3 in | |
| May | 58°F (14°C) | 3.4 in | |
| June | 67°F (19°C) | 3.9 in | |
| July | 71°F (22°C) | 3.9 in | Warmest |
| August | 69°F (20°C) | 4.1 in | Wettest |
| September | 61°F (16°C) | 3.6 in | |
| October | 49°F (9°C) | 2.3 in | |
| November | 35°F (2°C) | 2.2 in | |
| December | 22°F (-6°C) | 1.6 in |
DeForest has a seasonal temperature swing of 53°F / from 18°F in January to 71°F in July. Total annual precipitation is 33.0 inches, with August being the wettest month (4.1") and February the driest (1.1").