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Weather & Climate in Rochester, WI
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Rochester experiences four distinct seasons with an average annual temperature of 47°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 36.4 inches. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 787 feet.
Temperature
20°F Jan (-7°C)
71°F Jul (22°C)
| Annual Average | 46.7°F |
| 14% below US avg | |
| January Average | 20°F (-7°C) |
| July Average | 71°F (22°C) |
| Sunny Days | 260 days/yr |
Geography
| Elevation | 787 ft (240 m) |
| Area | 17.4 sq mi (45.1 km²) |
| Population Density | 217/sq mi |
| Coordinates | 42.7329°N, 88.2503°W |
| Timezone | America/Chicago |
| County | Walworth County County |
| Nearest Airport | Kenosha Regional (ENW) 19 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 38.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 74.8 / 100 |
| Social Vulnerability | 20.8 / 100 |
| Community Resilience | 80.3 / 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
6 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 | 87 km | 10 km |
| Sep 2, 1999 | 8 km W of Amboy, Illinois | M3.5 | 149 km | 5 km |
| Nov 4, 2013 | 1 km SSW of Lyons, Illinois | M3.2 | 110 km | 1 km |
| Jul 15, 2024 | 2 km WNW of Somonauk, Illinois | M3.1 | 127 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 | 85 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
467 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 45 fatalities, 1,228 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 27, 1984 | EF4 | 29 km | 6.5 mi | 1 |
| Apr 4, 1981 | EF4 | 78 km | 1.8 mi | 3 |
| Sep 28, 1972 | EF4 | 59 km | 5.2 mi | 0 |
| Apr 21, 1967 | EF4 | 79 km | 25.5 mi | 24 |
| Apr 21, 1967 | EF4 | 65 km | 8.8 mi | 1 |
| Apr 11, 1965 | EF4 | 58 km | 9.1 mi | 6 |
| Aug 22, 1964 | EF4 | 77 km | 2.2 mi | 0 |
| Jan 7, 2008 | EF3 | 21 km | 10.8 mi | 0 |
| Jan 7, 2008 | EF3 | 61 km | 13.2 mi | 0 |
| Aug 18, 2005 | EF3 | 98 km | 18.6 mi | 1 |
| Jun 5, 1980 | EF3 | 61 km | 10.7 mi | 0 |
| Jun 4, 1975 | EF3 | 97 km | 2.3 mi | 0 |
| Apr 21, 1974 | EF3 | 100 km | 22.2 mi | 0 |
| Apr 21, 1974 | EF3 | 94 km | 58.6 mi | 2 |
| Jan 24, 1967 | EF3 | 93 km | 24.9 mi | 0 |
| Jul 19, 1963 | EF3 | 17 km | 10.6 mi | 0 |
| Jun 22, 2024 | EF2 | 71 km | 6.0 mi | 0 |
| Feb 8, 2024 | EF2 | 88 km | 25.9 mi | 0 |
| Nov 22, 2010 | EF2 | 74 km | 18.1 mi | 0 |
| Jul 22, 2010 | EF2 | 15 km | 1.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
7 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (1,524 acres, 2006).
| Year | Name | Acres Burned | Distance |
| 2006 | UNNAMED | 1,524 | 93 km |
| 2010 | RX BURN | 1,236 | 93 km |
| 1994 | SOMMERS | 938 | 99 km |
| 1988 | PEACHY RD | 812 | 96 km |
| 2024 | IBSP SOUTH F1 RX | 690 | 51 km |
| 2007 | TOWER RD 2 | 592 | 96 km |
| 2024 | RX-HWY Y - SOUTH | 553 | 48 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-7°C) | 1.5 in | Coldest |
| February | 23°F (-5°C) | 1.2 in | Driest |
| March | 34°F (1°C) | 2.4 in | |
| April | 46°F (8°C) | 3.4 in | |
| May | 57°F (14°C) | 3.0 in | |
| June | 67°F (19°C) | 3.9 in | |
| July | 71°F (22°C) | 4.1 in | Warmest, Wettest |
| August | 69°F (21°C) | 3.9 in | |
| September | 62°F (16°C) | 3.7 in | |
| October | 50°F (10°C) | 2.5 in | |
| November | 37°F (3°C) | 2.5 in | |
| December | 24°F (-4°C) | 1.9 in |
Rochester has a seasonal temperature swing of 51°F / from 20°F in January to 71°F in July. Total annual precipitation is 34.0 inches, with July being the wettest month (4.1") and February the driest (1.2").