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Oswego, IL

Full City Profile · Illinois · Kendall County County

3.9 /5.0
B+ Good
35,463 Population 2,240/sq mi density
$119,881 Median Income $46,279 per capita
$319,000 Home Value $413,257 Zillow
$1,823 Median Rent 34.7% income on rent
50°F Avg Temperature 275 sunny days/yr
64 Violent Crime/100K 945 property/100K
B+
Overall
3.9 / 5.0
Good overall score based on economy, affordability, safety and education
A+
Economy
5.0 / 5.0
$119,881 median income, 1.9% unemployment
A+
Affordability
5.0 / 5.0
$319,000 home value, $1,823/mo rent
F
Safety
1.0 / 5.0
64 violent crimes/100K
A
Education
4.5 / 5.0
43.5% bachelor's degree or higher
Oswego experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 23°F in January while summers reach 74°F in July. The area gets 275 sunny days per year. Annual precipitation totals 39.5 inches. The area receives 27.9 inches of snow annually. Air quality is rated Good with a median AQI of 43.

Temperature

23°F Jan (-5°C) 74°F Jul (24°C)
Annual Average50.2°F
7% below US avg
January Average23°F (-5°C)
July Average74°F (24°C)
Sunny Days275 days/yr

Geography

Elevation659 ft (201 m)
Area15.0 sq mi (39.0 km²)
Population Density2,240/sq mi
Coordinates41.6832°N, 88.3388°W
TimezoneAmerica/Chicago
CountyKendall County County
Nearest AirportJoliet Regional (JOT)
14 miles away

Precipitation & Snow

Annual Rainfall 39.5"
4% above US avg
Snowfall 27.9"
Wettest Month (Jun) 4.21"
Driest Month (Feb) 1.34"

Air Quality

AQI Median43.0
RatingGood

Natural Hazard Risk

Overall RiskRelatively Low
Risk Score80.3 / 100
Social Vulnerability10.6 / 100
Community Resilience96.0 / 100

Hazard Breakdown

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

Earthquake History

8 earthquakes (M2.5+) within 150 km since 1990. Strongest: M4.2. Most recent: M2.6 on Mar 15, 2025.

Jun 28, 2004 12 km NW of Dayton, Illinois M4.2 53 km
Feb 10, 2010 2 km NW of Lily Lake, Illinois M3.8 34 km
Sep 2, 1999 8 km W of Amboy, Illinois M3.5 91 km
Nov 4, 2013 1 km SSW of Lyons, Illinois M3.2 45 km
Jul 15, 2024 2 km WNW of Somonauk, Illinois M3.1 31 km
Mar 25, 2015 3 km WNW of Lake in the Hills, Illinois M2.9 56 km
Jun 10, 2013 4 km NNE of Virgil, Illinois M2.6 37 km
Mar 15, 2025 6 km W of Dwight, Illinois M2.6 68 km
Source: USGS (M2.5+, 1990–2025)

Tornado History

629 tornadoes (EF0+) within 100 km since 1950. Strongest: EF5. Total: 122 fatalities, 2,279 injuries.

Date Rating Distance Fatalities
Aug 28, 1990 EF5 1 km 29
Apr 9, 2015 EF4 81 km 2
Jun 29, 1979 EF4 20 km 0
Jun 13, 1976 EF4 28 km 2
Sep 28, 1972 EF4 77 km 0
Apr 21, 1967 EF4 42 km 33
Apr 21, 1967 EF4 52 km 1
Apr 21, 1967 EF4 77 km 24
Apr 11, 1965 EF4 60 km 6
Apr 17, 1963 EF4 59 km 1
Jun 20, 2021 EF3 14 km 0
Feb 28, 2017 EF3 65 km 2
Jun 22, 2015 EF3 42 km 0
Jun 5, 2010 EF3 73 km 0
Jun 5, 2010 EF3 85 km 0
Jan 7, 2008 EF3 96 km 0
Jan 7, 2008 EF3 88 km 0
Apr 20, 2004 EF3 92 km 8
Mar 27, 1991 EF3 23 km 0
Apr 27, 1984 EF3 15 km 1
Source: NOAA SPC (EF0+, 1950–2024)

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 7 121 km
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.

Wildfire History

11 wildfires (100+ acres) within 100 km. Largest: UNNAMED (1,741 ac, 2019).

Year Name Acres Distance
2019 UNNAMED 1,741 37 km
2019 UNNAMED 1,664 40 km
2021 NORTHEAST PRAIRIE UNIT 3 978 44 km
2024 NORTHEAST PRAIRIE 3 RX 938 42 km
1986 OGDEN DUNS 863 94 km
2021 UNNAMED 738 41 km
2021 MIDDLE GRANT CREEK 700 38 km
2019 UNNAMED 698 41 km
2024 IBSP SOUTH F1 RX 690 91 km
2021 21-INDU TOLLESTON DUNES EAST 594 94 km
2017 UNNAMED 549 38 km
Source: NIFC/IRWIN (100+ acres)

Monthly Weather

Month Avg Temperature Precipitation Summary
January 23°F (-5°C) 1.5 in Coldest
February 26°F (-3°C) 1.3 in Driest
March 37°F (3°C) 2.6 in
April 49°F (9°C) 3.8 in
May 60°F (16°C) 3.9 in
June 70°F (21°C) 4.2 in Wettest
July 74°F (24°C) 3.9 in Warmest
August 71°F (22°C) 4.0 in
September 64°F (18°C) 3.8 in
October 52°F (11°C) 2.7 in
November 39°F (4°C) 3.0 in
December 26°F (-3°C) 2.3 in

Oswego has a seasonal temperature swing of 51°F / from 23°F in January to 74°F in July. Total annual precipitation is 37.1 inches, with June being the wettest month (4.2") and February the driest (1.3").

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