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Weather & Climate in Union Grove, WI

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

Union Grove experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 20°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 35.3 inches. The area receives 40.5 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 784 feet.

Temperature

20°F Jan (-7°C) 71°F Jul (22°C)
Annual Average46.4°F
14% below US avg
January Average20°F (-7°C)
July Average71°F (22°C)
Sunny Days260 days/yr

Geography

Elevation784 ft (239 m)
Area2.5 sq mi (6.4 km²)
Population Density1,918/sq mi
Coordinates42.6864°N, 88.0495°W
TimezoneAmerica/Chicago
CountyWalworth County County
Nearest AirportKenosha Regional (ENW)
9 miles away

Precipitation & Snow

Annual Rainfall 35.3"
7% below US avg
Snowfall 40.5"
Wettest Month (Aug) 3.94"
Driest Month (Feb) 1.22"

Air Quality

AQI Median38.0
RatingGood

Natural Hazard Risk

Overall RiskRelatively Low
Risk Score74.8 / 100
Social Vulnerability20.8 / 100
Community Resilience80.3 / 100

Hazard Breakdown

Tornado Relatively Moderate
Hurricane Very Low
Earthquake Very Low
Wildfire Very Low
Flood Relatively Moderate
Hail Relatively High
Strong Wind Relatively Moderate
Heat Wave Relatively Low
Winter Weather Relatively Low
Lightning Relatively Moderate
Ice Storm Relatively Low
Drought Relatively Low
Cold Wave Relatively Moderate
Landslide Relatively Low
Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

5 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.8.

Feb 10, 2010 2 km NW of Lily Lake, Illinois M3.8 88 km 10 km
Nov 4, 2013 1 km SSW of Lyons, Illinois M3.2 100 km 1 km
Jul 15, 2024 2 km WNW of Somonauk, Illinois M3.1 128 km 10 km
Mar 25, 2015 3 km WNW of Lake in the Hills, Illinois M2.9 61 km 6 km
Jun 10, 2013 4 km NNE of Virgil, Illinois M2.6 86 km 5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

417 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 42 fatalities, 1,292 injuries.

Date Rating Distance Path Fatalities
Apr 27, 1984 EF4 42 km 6.5 mi 1
Apr 4, 1981 EF4 84 km 1.8 mi 3
Sep 28, 1972 EF4 48 km 5.2 mi 0
Apr 21, 1967 EF4 88 km 25.5 mi 24
Apr 21, 1967 EF4 62 km 8.8 mi 1
Apr 11, 1965 EF4 59 km 9.1 mi 6
Aug 22, 1964 EF4 78 km 2.2 mi 0
Jan 7, 2008 EF3 72 km 13.2 mi 0
Jan 7, 2008 EF3 28 km 10.8 mi 0
Jun 5, 1980 EF3 77 km 10.7 mi 0
Jul 19, 1963 EF3 20 km 10.6 mi 0
Jun 22, 2024 EF2 87 km 6.0 mi 0
Nov 22, 2010 EF2 85 km 18.1 mi 0
Jul 22, 2010 EF2 23 km 1.0 mi 0
Jun 21, 2010 EF2 42 km 5.2 mi 0
Jun 1, 2000 EF2 92 km 17.0 mi 0
Jun 25, 1998 EF2 93 km 2.5 mi 0
May 18, 1997 EF2 30 km 6.0 mi 0
Apr 19, 1996 EF2 32 km 2.0 mi 0
Sep 28, 1986 EF2 59 km 9.0 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 7 146 km
Source: NOAA/NCEI Historical Tsunami Database.

Wildfire History

2 wildfires (100+ acres) recorded within 100 km. Largest: IBSP SOUTH F1 RX (690 acres, 2024).

Year Name Acres Burned Distance
2024 IBSP SOUTH F1 RX 690 37 km
2024 RX-HWY Y - SOUTH 553 65 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 20°F (-7°C) 1.6 in Coldest
February 23°F (-5°C) 1.2 in Driest
March 34°F (1°C) 2.3 in
April 45°F (7°C) 3.5 in
May 56°F (14°C) 3.1 in
June 66°F (19°C) 3.8 in
July 71°F (22°C) 3.9 in Warmest
August 69°F (21°C) 3.9 in Wettest
September 62°F (16°C) 3.7 in
October 50°F (10°C) 2.4 in
November 37°F (3°C) 2.5 in
December 25°F (-4°C) 2.0 in

Union Grove has a seasonal temperature swing of 51°F / from 20°F in January to 71°F in July. Total annual precipitation is 33.9 inches, with August being the wettest month (3.9") and February the driest (1.2").

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