Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Winthrop Harbor experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 23°F in January while summers reach 72°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 35.3 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 657 feet.
Temperature
23°F Jan (-5°C)72°F Jul (22°C)
Annual Average
48.3°F
11% below US avg
January Average
23°F (-5°C)
July Average
72°F (22°C)
Sunny Days
260 days/yr
Geography
Elevation
657 ft (200 m)
Area
1.9 sq mi (4.8 km²)
Population Density
1,433/sq mi
Coordinates
42.4806°N, 87.8296°W
Timezone
America/Chicago
County
Kenosha County County
Nearest Airport
Kenosha Regional (ENW) 9 miles away
Precipitation & Snow
Annual Rainfall35.3"
7% below US avg
Wettest Month (Aug)3.94"
Driest Month (Feb)1.34"
Air Quality
AQI Median
43.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively Moderate
Risk Score
85.0 / 100
Social Vulnerability
23.7 / 100
Community Resilience
97.3 / 100
Hazard Breakdown
Tornado
Relatively High
Hurricane
Very Low
Earthquake
Relatively Low
Wildfire
Very Low
Flood
Relatively Moderate
Hail
Relatively Moderate
Strong Wind
Relatively High
Heat Wave
Relatively Moderate
Winter Weather
Relatively Low
Lightning
Relatively High
Ice Storm
Relatively Low
Drought
Relatively Low
Cold Wave
Relatively High
Landslide
Very Low
Coastal Flood
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.
Jun 28, 2004
12 km NW of Dayton, Illinois
M4.2
144 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
79 km
10 km
Nov 4, 2013
1 km SSW of Lyons, Illinois
M3.2
76 km
1 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
118 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
55 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
78 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
380 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF5. Total: 100 fatalities, 2,069 injuries.
Date
Rating
Distance
Path
Fatalities
Aug 28, 1990
EF5
99 km
16.4 mi
29
Apr 27, 1984
EF4
71 km
6.5 mi
1
Jun 13, 1976
EF4
91 km
3.3 mi
2
Sep 28, 1972
EF4
23 km
5.2 mi
0
Apr 21, 1967
EF4
94 km
25.5 mi
24
Apr 21, 1967
EF4
90 km
15.0 mi
33
Apr 21, 1967
EF4
52 km
8.8 mi
1
Apr 11, 1965
EF4
54 km
9.1 mi
6
Jun 20, 2021
EF3
87 km
17.6 mi
0
Jan 7, 2008
EF3
83 km
13.2 mi
0
Jan 7, 2008
EF3
42 km
10.8 mi
0
Jul 19, 1963
EF3
36 km
10.6 mi
0
Nov 22, 2010
EF2
95 km
18.1 mi
0
Jul 22, 2010
EF2
52 km
1.0 mi
0
Jun 21, 2010
EF2
70 km
5.2 mi
0
May 18, 1997
EF2
19 km
6.0 mi
0
Apr 19, 1996
EF2
3 km
2.0 mi
0
Sep 28, 1986
EF2
85 km
9.0 mi
0
Aug 4, 1980
EF2
78 km
0.1 mi
0
Jul 16, 1980
EF2
70 km
1.4 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
117 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
8 km
2024
RX-HWY Y - SOUTH
553
92 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
23°F (-5°C)
1.7 in
Coldest
February
28°F (-2°C)
1.3 in
Driest
March
34°F (1°C)
2.4 in
April
44°F (7°C)
3.7 in
May
54°F (12°C)
3.3 in
June
64°F (18°C)
3.6 in
July
72°F (22°C)
3.5 in
Warmest
August
70°F (21°C)
3.9 in
Wettest
September
63°F (17°C)
3.7 in
October
53°F (11°C)
2.4 in
November
42°F (5°C)
2.6 in
December
30°F (-1°C)
2.2 in
Winthrop Harbor has a seasonal temperature swing of 48°F / from 23°F in January to 72°F in July. Total annual precipitation is 34.5 inches, with August being the wettest month (3.9") and February the driest (1.3").
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