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Weather & Climate in Oswego, IN
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Oswego experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 24°F in January while summers reach 73°F in July. The area gets 275 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 39.8 inches. The area receives 47.3 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 41. The city sits at an elevation of 842 feet.
Temperature
24°F Jan (-4°C)
73°F Jul (23°C)
| Annual Average | 50.1°F |
| 7% below US avg | |
| January Average | 24°F (-4°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 842 ft (257 m) |
| Area | 0.5 sq mi (1.2 km²) |
| Population Density | 604/sq mi |
| Coordinates | 41.3224°N, 85.7871°W |
| Timezone | America/Indiana/Indianapolis |
| County | Kosciusko County County |
| Nearest Airport | South Bend International (SBN) 38 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 41.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 66.3 / 100 |
| Social Vulnerability | 44.2 / 100 |
| Community Resilience | 79.1 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Low |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Very 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: M4.2.
| May 2, 2015 | 5 km S of Galesburg, Michigan | M4.2 | 106 km | 4 km |
| Jun 30, 2015 | 5 km NNE of Burlington, Michigan | M3.3 | 110 km | 5 km |
| Jan 26, 2012 | 5 km NE of Topeka, Indiana | M3.0 | 38 km | 5 km |
| Apr 17, 1990 | 8 km NW of Fort Recovery, Ohio | M3.0 | 124 km | 5 km |
| Jun 12, 2015 | 6 km NW of Convoy, Ohio | M2.6 | 95 km | 5 km |
| Jan 30, 2004 | 2 km S of Rockford, Ohio | M2.5 | 120 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
498 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 143 fatalities, 1,852 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 11, 1965 | EF4 | 92 km | 52.5 mi | 4 |
| Apr 11, 1965 | EF4 | 34 km | 21.6 mi | 5 |
| Apr 11, 1965 | EF4 | 45 km | 37.0 mi | 36 |
| Apr 11, 1965 | EF4 | 84 km | 80.5 mi | 21 |
| Apr 11, 1965 | EF4 | 32 km | 21.2 mi | 31 |
| Apr 11, 1965 | EF4 | 69 km | 90.3 mi | 23 |
| Mar 6, 1956 | EF4 | 86 km | 1.9 mi | 1 |
| Mar 31, 2023 | EF3 | 95 km | 6.4 mi | 0 |
| May 27, 2019 | EF3 | 48 km | 13.7 mi | 0 |
| May 27, 2019 | EF3 | 89 km | 12.8 mi | 0 |
| Aug 24, 2016 | EF3 | 75 km | 5.2 mi | 0 |
| Jun 5, 2010 | EF3 | 83 km | 7.5 mi | 0 |
| Oct 18, 2007 | EF3 | 32 km | 20.3 mi | 0 |
| May 30, 2004 | EF3 | 72 km | 4.5 mi | 0 |
| Oct 24, 2001 | EF3 | 63 km | 47.0 mi | 1 |
| Mar 27, 1991 | EF3 | 64 km | 21.0 mi | 1 |
| May 15, 1986 | EF3 | 96 km | 1.2 mi | 0 |
| Mar 12, 1976 | EF3 | 72 km | 12.1 mi | 0 |
| Apr 3, 1974 | EF3 | 29 km | 36.2 mi | 5 |
| May 16, 1968 | EF3 | 66 km | 50.3 mi | 1 |
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 | 100 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-4°C) | 1.9 in | Coldest |
| February | 27°F (-3°C) | 1.8 in | Driest |
| March | 37°F (3°C) | 2.8 in | |
| April | 48°F (9°C) | 3.7 in | |
| May | 60°F (15°C) | 3.7 in | |
| June | 69°F (20°C) | 4.1 in | Wettest |
| July | 73°F (23°C) | 3.7 in | Warmest |
| August | 71°F (21°C) | 3.7 in | |
| September | 64°F (18°C) | 3.5 in | |
| October | 52°F (11°C) | 2.8 in | |
| November | 40°F (5°C) | 3.1 in | |
| December | 29°F (-2°C) | 2.8 in |
Oswego has a seasonal temperature swing of 48°F / from 24°F in January to 73°F in July. Total annual precipitation is 37.5 inches, with June being the wettest month (4.1") and February the driest (1.8").