Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Round Lake experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 21°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 38.5 inches. The area receives 43.1 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 767 feet.
Temperature
21°F Jan (-6°C)72°F Jul (22°C)
Annual Average
47.9°F
11% below US avg
January Average
21°F (-6°C)
July Average
72°F (22°C)
Sunny Days
260 days/yr
Geography
Elevation
767 ft (234 m)
Area
5.6 sq mi (14.4 km²)
Population Density
3,343/sq mi
Coordinates
42.3432°N, 88.1021°W
Timezone
America/Chicago
County
McHenry County County
Nearest Airport
Kenosha Regional (ENW) 20 miles away
Precipitation & Snow
Annual Rainfall38.5"
1% above US avg
Snowfall43.1"
Wettest Month (Aug)4.06"
Driest Month (Feb)1.26"
Air Quality
AQI Median
43.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively Moderate
Risk Score
90.8 / 100
Social Vulnerability
10.6 / 100
Community Resilience
84.0 / 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 Low
Winter Weather
Relatively Moderate
Lightning
Relatively Moderate
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+) recorded within 150 km since 1990.
Strongest on record: M4.2.
Jun 28, 2004
12 km NW of Dayton, Illinois
M4.2
118 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
53 km
10 km
Sep 2, 1999
8 km W of Amboy, Illinois
M3.5
130 km
5 km
Nov 4, 2013
1 km SSW of Lyons, Illinois
M3.2
65 km
1 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
92 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
28 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
52 km
5 km
Mar 15, 2025
6 km W of Dwight, Illinois
M2.6
144 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
489 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF5. Total: 106 fatalities, 2,185 injuries.
Date
Rating
Distance
Path
Fatalities
Aug 28, 1990
EF5
77 km
16.4 mi
29
Apr 27, 1984
EF4
74 km
6.5 mi
1
Jun 29, 1979
EF4
92 km
5.4 mi
0
Jun 13, 1976
EF4
75 km
3.3 mi
2
Sep 28, 1972
EF4
20 km
5.2 mi
0
Apr 21, 1967
EF4
78 km
15.0 mi
33
Apr 21, 1967
EF4
69 km
25.5 mi
24
Apr 21, 1967
EF4
26 km
8.8 mi
1
Apr 11, 1965
EF4
27 km
9.1 mi
6
Jun 20, 2021
EF3
67 km
17.6 mi
0
Jan 7, 2008
EF3
30 km
10.8 mi
0
Jan 7, 2008
EF3
60 km
13.2 mi
0
Mar 27, 1991
EF3
85 km
15.0 mi
0
Apr 27, 1984
EF3
90 km
9.0 mi
1
Mar 12, 1976
EF3
82 km
22.6 mi
0
Jul 19, 1963
EF3
29 km
10.6 mi
0
Jun 22, 2024
EF2
89 km
6.0 mi
0
Nov 22, 2010
EF2
71 km
18.1 mi
0
Jul 22, 2010
EF2
59 km
1.0 mi
0
Jun 21, 2010
EF2
67 km
5.2 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
124 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
25 km
2024
RX-HWY Y - SOUTH
553
87 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
21°F (-6°C)
1.6 in
Coldest
February
24°F (-4°C)
1.3 in
Driest
March
35°F (1°C)
2.5 in
April
46°F (8°C)
3.6 in
May
57°F (14°C)
3.4 in
June
67°F (19°C)
3.8 in
July
72°F (22°C)
4.0 in
Warmest
August
70°F (21°C)
4.1 in
Wettest
September
62°F (17°C)
3.8 in
October
51°F (11°C)
2.4 in
November
38°F (3°C)
2.6 in
December
26°F (-4°C)
2.1 in
Round Lake has a seasonal temperature swing of 51°F / from 21°F in January to 72°F in July. Total annual precipitation is 35.2 inches, with August being the wettest month (4.1") and February the driest (1.3").
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