Weather & Climate in Roscoe, IL
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Roscoe has a cool climate with an average annual temperature of 45°F (7°C). Winters average 18°F in January while summers reach 70°F in July. Annual precipitation totals 38.6 inches. The area receives 38.0 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. 69% of days have good air quality. The city sits at an elevation of 746 feet.
Temperature
18°F Jan (-8°C)
70°F Jul (21°C)
| Annual Average | 45.4°F |
| 16% below US avg | |
| January Average | 18°F (-8°C) |
| July Average | 70°F (21°C) |
Geography
| Elevation | 746 ft (227 m) |
| Area | 10.4 sq mi (26.9 km²) |
| Population Density | 1,059/sq mi |
| Coordinates | 42.4256°N, 89.0095°W |
| Timezone | America/Chicago |
| County | Winnebago County County |
| Nearest Airport | Southern Wisconsin Regional (JVL) 14 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
| Good Days % | 69.0% |
| Unhealthy Days | 3 |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 92.4 / 100 |
| Social Vulnerability | 38.9 / 100 |
| Community Resilience | 68.5 / 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 Moderate |
| Lightning | Relatively High |
| Ice Storm | Relatively High |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
7 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.2.
| Jun 28, 2004 | 12 km NW of Dayton, Illinois | M4.2 | 108 km | 10 km |
| Feb 10, 2010 | 2 km NW of Lily Lake, Illinois | M3.8 | 66 km | 10 km |
| Sep 2, 1999 | 8 km W of Amboy, Illinois | M3.5 | 86 km | 5 km |
| Nov 4, 2013 | 1 km SSW of Lyons, Illinois | M3.2 | 120 km | 1 km |
| Jul 15, 2024 | 2 km WNW of Somonauk, Illinois | M3.1 | 90 km | 10 km |
| Mar 25, 2015 | 3 km WNW of Lake in the Hills, Illinois | M2.9 | 59 km | 6 km |
| Jun 10, 2013 | 4 km NNE of Virgil, Illinois | M2.6 | 64 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
599 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 83 fatalities, 1,575 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Aug 28, 1990 | EF5 | 99 km | 16.4 mi | 29 |
| Jun 7, 1984 | EF5 | 100 km | 36.0 mi | 9 |
| Apr 9, 2015 | EF4 | 68 km | 30.1 mi | 2 |
| Apr 27, 1984 | EF4 | 81 km | 6.5 mi | 1 |
| Sep 28, 1972 | EF4 | 95 km | 5.2 mi | 0 |
| Apr 21, 1967 | EF4 | 68 km | 8.8 mi | 1 |
| Apr 21, 1967 | EF4 | 24 km | 25.5 mi | 24 |
| Apr 11, 1965 | EF4 | 57 km | 9.1 mi | 6 |
| Jun 16, 2014 | EF3 | 78 km | 1.0 mi | 0 |
| Jan 7, 2008 | EF3 | 57 km | 10.8 mi | 0 |
| Jan 7, 2008 | EF3 | 15 km | 13.2 mi | 0 |
| Aug 18, 2005 | EF3 | 65 km | 18.6 mi | 1 |
| Jun 17, 1992 | EF3 | 66 km | 16.0 mi | 0 |
| Jun 5, 1980 | EF3 | 81 km | 10.7 mi | 0 |
| Aug 5, 1979 | EF3 | 65 km | 5.7 mi | 0 |
| Jun 30, 1977 | EF3 | 94 km | 6.1 mi | 0 |
| Jun 4, 1975 | EF3 | 91 km | 2.3 mi | 0 |
| Aug 2, 1967 | EF3 | 86 km | 0.1 mi | 2 |
| Apr 16, 1967 | EF3 | 76 km | 27.8 mi | 0 |
| Jan 24, 1967 | EF3 | 35 km | 24.9 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Wildfire History
3 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 | 98 km |
| 2024 | RX-HWY Y - SOUTH | 553 | 64 km |
| 2009 | COLD SPRINGS | 552 | 58 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 18°F (-8°C) | 1.7 in | Coldest, Driest |
| February | 22°F (-6°C) | 1.7 in | |
| March | 33°F (0°C) | 2.2 in | |
| April | 45°F (7°C) | 3.7 in | |
| May | 56°F (13°C) | 4.3 in | |
| June | 66°F (19°C) | 5.5 in | Wettest |
| July | 70°F (21°C) | 3.7 in | Warmest |
| August | 68°F (20°C) | 4.4 in | |
| September | 61°F (16°C) | 4.2 in | |
| October | 49°F (9°C) | 3.0 in | |
| November | 35°F (2°C) | 2.5 in | |
| December | 24°F (-5°C) | 1.9 in |
Roscoe has a seasonal temperature swing of 52°F / from 18°F in January to 70°F in July. Total annual precipitation is 38.7 inches, with June being the wettest month (5.5") and January the driest (1.7").