Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Prairie Grove experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 22°F in January while summers reach 73°F in July. The area gets 260 sunny days per year, above the national average. Annual precipitation totals 37.0 inches. The area receives 34.5 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 763 feet.
Temperature
22°F Jan (-6°C)73°F Jul (23°C)
Annual Average
48.6°F
10% below US avg
January Average
22°F (-6°C)
July Average
73°F (23°C)
Sunny Days
260 days/yr
Geography
Elevation
763 ft (233 m)
Area
2.2 sq mi (5.7 km²)
Population Density
329/sq mi
Coordinates
42.2739°N, 88.2699°W
Timezone
America/Chicago
County
McHenry County County
Nearest Airport
Chicago O'Hare International (ORD) 28 miles away
Precipitation & Snow
Annual Rainfall37.0"
3% below US avg
Snowfall34.5"
Wettest Month (Aug)4.13"
Driest Month (Feb)1.22"
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
105 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
39 km
10 km
Sep 2, 1999
8 km W of Amboy, Illinois
M3.5
114 km
5 km
Nov 4, 2013
1 km SSW of Lyons, Illinois
M3.2
64 km
1 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
79 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
12 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
37 km
5 km
Mar 15, 2025
6 km W of Dwight, Illinois
M2.6
133 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
541 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF5. Total: 111 fatalities, 2,292 injuries.
Date
Rating
Distance
Path
Fatalities
Aug 28, 1990
EF5
66 km
16.4 mi
29
Apr 9, 2015
EF4
96 km
30.1 mi
2
Apr 27, 1984
EF4
79 km
6.5 mi
1
Jun 29, 1979
EF4
84 km
5.4 mi
0
Jun 13, 1976
EF4
71 km
3.3 mi
2
Sep 28, 1972
EF4
33 km
5.2 mi
0
Apr 21, 1967
EF4
54 km
25.5 mi
24
Apr 21, 1967
EF4
76 km
15.0 mi
33
Apr 21, 1967
EF4
14 km
8.8 mi
1
Apr 11, 1965
EF4
11 km
9.1 mi
6
Jun 20, 2021
EF3
59 km
17.6 mi
0
Jan 7, 2008
EF3
31 km
10.8 mi
0
Jan 7, 2008
EF3
48 km
13.2 mi
0
Mar 27, 1991
EF3
78 km
15.0 mi
0
Apr 27, 1984
EF3
81 km
9.0 mi
1
Jun 30, 1977
EF3
98 km
6.1 mi
0
Mar 12, 1976
EF3
72 km
22.6 mi
0
Jan 24, 1967
EF3
97 km
24.9 mi
0
Jul 19, 1963
EF3
34 km
10.6 mi
0
Jul 15, 2024
EF2
99 km
34.6 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
131 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
40 km
2024
RX-HWY Y - SOUTH
553
86 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
22°F (-6°C)
1.5 in
Coldest
February
25°F (-4°C)
1.2 in
Driest
March
36°F (2°C)
2.5 in
April
47°F (8°C)
3.6 in
May
58°F (15°C)
3.5 in
June
68°F (20°C)
4.1 in
July
73°F (23°C)
4.1 in
Warmest
August
71°F (21°C)
4.1 in
Wettest
September
63°F (17°C)
3.9 in
October
51°F (11°C)
2.4 in
November
38°F (3°C)
2.8 in
December
26°F (-4°C)
2.1 in
Prairie Grove has a seasonal temperature swing of 51°F / from 22°F in January to 73°F in July. Total annual precipitation is 35.7 inches, with August being the wettest month (4.1") and February the driest (1.2").
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