Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Spring Grove experiences four distinct seasons with an average annual temperature of 47°F (8°C). Winters average 21°F in January while summers reach 71°F in July. Annual precipitation totals 40.2 inches. The area receives 43.4 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 43. 67% of days have good air quality. The city sits at an elevation of 797 feet.
Temperature
21°F Jan (-6°C)71°F Jul (21°C)
Annual Average
47.0°F
13% below US avg
January Average
21°F (-6°C)
July Average
71°F (21°C)
Geography
Elevation
797 ft (243 m)
Area
3.4 sq mi (8.8 km²)
Population Density
648/sq mi
Coordinates
42.4507°N, 88.2402°W
Timezone
America/Chicago
County
McHenry County County
Nearest Airport
Kenosha Regional (ENW) 19 miles away
Precipitation & Snow
Annual Rainfall40.2"
6% above US avg
Snowfall43.4"
Wettest Month (Jun)5.23"
Driest Month (Jan)1.72"
Air Quality
AQI Median
43.0
Rating
Good
Good Days %
66.9%
Unhealthy Days
1
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
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
123 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
58 km
10 km
Sep 2, 1999
8 km W of Amboy, Illinois
M3.5
128 km
5 km
Nov 4, 2013
1 km SSW of Lyons, Illinois
M3.2
80 km
1 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
98 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
31 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
56 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
502 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF5. Total: 104 fatalities, 2,149 injuries.
Date
Rating
Distance
Path
Fatalities
Aug 28, 1990
EF5
86 km
16.4 mi
29
Apr 27, 1984
EF4
60 km
6.5 mi
1
Jun 13, 1976
EF4
89 km
3.3 mi
2
Sep 28, 1972
EF4
36 km
5.2 mi
0
Apr 21, 1967
EF4
62 km
25.5 mi
24
Apr 21, 1967
EF4
93 km
15.0 mi
33
Apr 21, 1967
EF4
34 km
8.8 mi
1
Apr 11, 1965
EF4
28 km
9.1 mi
6
Jun 20, 2021
EF3
79 km
17.6 mi
0
Jan 7, 2008
EF3
49 km
13.2 mi
0
Jan 7, 2008
EF3
13 km
10.8 mi
0
Mar 27, 1991
EF3
98 km
15.0 mi
0
Jun 5, 1980
EF3
87 km
10.7 mi
0
Mar 12, 1976
EF3
92 km
22.6 mi
0
Jan 24, 1967
EF3
94 km
24.9 mi
0
Jul 19, 1963
EF3
14 km
10.6 mi
0
Jun 22, 2024
EF2
74 km
6.0 mi
0
Feb 8, 2024
EF2
94 km
25.9 mi
0
Nov 22, 2010
EF2
61 km
18.1 mi
0
Jul 22, 2010
EF2
46 km
1.0 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
140 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
35 km
2024
RX-HWY Y - SOUTH
553
71 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
21°F (-6°C)
1.7 in
Coldest, Driest
February
23°F (-5°C)
3.0 in
March
35°F (2°C)
2.4 in
April
46°F (8°C)
3.7 in
May
57°F (14°C)
4.1 in
June
67°F (19°C)
5.2 in
Wettest
July
71°F (21°C)
4.6 in
Warmest
August
69°F (20°C)
4.0 in
September
62°F (17°C)
3.6 in
October
50°F (10°C)
3.2 in
November
38°F (3°C)
2.6 in
December
27°F (-3°C)
2.1 in
Spring Grove has a seasonal temperature swing of 50°F / from 21°F in January to 71°F in July. Total annual precipitation is 40.2 inches, with June being the wettest month (5.2") and January the driest (1.7").