Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Darien 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 36.7 inches. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 926 feet.
Temperature
21°F Jan (-6°C)72°F Jul (22°C)
Annual Average
47.6°F
12% below US avg
January Average
21°F (-6°C)
July Average
72°F (22°C)
Sunny Days
260 days/yr
Geography
Elevation
926 ft (282 m)
Area
0.5 sq mi (1.3 km²)
Population Density
773/sq mi
Coordinates
42.6007°N, 88.7128°W
Timezone
America/Chicago
County
Walworth County County
Nearest Airport
Southern Wisconsin Regional (JVL) 17 miles away
Precipitation & Snow
Annual Rainfall36.7"
3% below US avg
Wettest Month (Aug)4.09"
Driest Month (Feb)1.14"
Air Quality
AQI Median
38.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively Low
Risk Score
74.8 / 100
Social Vulnerability
20.8 / 100
Community Resilience
80.3 / 100
Hazard Breakdown
Tornado
Relatively Moderate
Hurricane
Very Low
Earthquake
Very Low
Wildfire
Very Low
Flood
Relatively Moderate
Hail
Relatively High
Strong Wind
Relatively Moderate
Heat Wave
Relatively Low
Winter Weather
Relatively Low
Lightning
Relatively Moderate
Ice Storm
Relatively Low
Drought
Relatively Low
Cold Wave
Relatively Moderate
Landslide
Relatively 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
128 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
72 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
115 km
1 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
106 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
54 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
70 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
578 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF4. Total: 47 fatalities, 1,275 injuries.
Date
Rating
Distance
Path
Fatalities
Apr 9, 2015
EF4
96 km
30.1 mi
2
Apr 27, 1984
EF4
51 km
6.5 mi
1
Sep 28, 1972
EF4
78 km
5.2 mi
0
Apr 21, 1967
EF4
46 km
25.5 mi
24
Apr 21, 1967
EF4
62 km
8.8 mi
1
Apr 11, 1965
EF4
50 km
9.1 mi
6
Jun 16, 2014
EF3
82 km
1.0 mi
0
Jan 7, 2008
EF3
32 km
10.8 mi
0
Jan 7, 2008
EF3
25 km
13.2 mi
0
Aug 18, 2005
EF3
69 km
18.6 mi
1
Jun 17, 1992
EF3
74 km
16.0 mi
0
Jun 5, 1980
EF3
59 km
10.7 mi
0
Apr 7, 1980
EF3
100 km
1.2 mi
0
Aug 5, 1979
EF3
96 km
5.7 mi
0
Jun 4, 1975
EF3
82 km
2.3 mi
0
Apr 21, 1974
EF3
100 km
58.6 mi
2
Aug 2, 1967
EF3
84 km
0.1 mi
2
Jan 24, 1967
EF3
54 km
24.9 mi
0
Jul 19, 1963
EF3
38 km
10.6 mi
0
Jun 22, 2024
EF2
33 km
6.0 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
3 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
77 km
2024
RX-HWY Y - SOUTH
553
41 km
2009
COLD SPRINGS
552
75 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
21°F (-6°C)
1.3 in
Coldest
February
23°F (-5°C)
1.1 in
Driest
March
34°F (1°C)
2.4 in
April
46°F (8°C)
3.5 in
May
58°F (15°C)
3.3 in
June
68°F (20°C)
3.9 in
July
72°F (22°C)
4.1 in
Warmest
August
70°F (21°C)
4.1 in
Wettest
September
62°F (17°C)
3.9 in
October
50°F (10°C)
2.6 in
November
37°F (3°C)
2.6 in
December
24°F (-5°C)
1.9 in
Darien has a seasonal temperature swing of 51°F / from 21°F in January to 72°F in July. Total annual precipitation is 34.7 inches, with August being the wettest month (4.1") and February the driest (1.1").