Temperature, precipitation, air quality, natural hazards, and monthly weather data.
South Wayne experiences four distinct seasons with an average annual temperature of 47°F (9°C). Winters average 19°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 39.7 inches. The area receives 41.5 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 842 feet.
Temperature
19°F Jan (-7°C)73°F Jul (23°C)
Annual Average
47.3°F
12% below US avg
January Average
19°F (-7°C)
July Average
73°F (23°C)
Sunny Days
260 days/yr
Geography
Elevation
842 ft (257 m)
Area
0.8 sq mi (2.1 km²)
Population Density
572/sq mi
Coordinates
42.5676°N, 89.8761°W
Timezone
America/Chicago
County
Green County County
Nearest Airport
Southern Wisconsin Regional (JVL) 43 miles away
Precipitation & Snow
Annual Rainfall39.7"
5% above US avg
Snowfall41.5"
Wettest Month (Aug)4.17"
Driest Month (Jan)1.10"
Air Quality
AQI Median
38.0
Rating
Good
Natural Hazard Risk
Overall Risk
Relatively Low
Risk Score
46.4 / 100
Social Vulnerability
17.8 / 100
Community Resilience
81.9 / 100
Hazard Breakdown
Tornado
Relatively Moderate
Hurricane
Very Low
Earthquake
Very Low
Wildfire
Very Low
Flood
Relatively Low
Hail
Relatively Moderate
Strong Wind
Relatively Moderate
Heat Wave
Relatively Low
Winter Weather
Relatively Low
Lightning
Relatively Low
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
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
147 km
10 km
Feb 10, 2010
2 km NW of Lily Lake, Illinois
M3.8
132 km
10 km
Sep 2, 1999
8 km W of Amboy, Illinois
M3.5
101 km
5 km
Jul 15, 2024
2 km WNW of Somonauk, Illinois
M3.1
141 km
10 km
Mar 25, 2015
3 km WNW of Lake in the Hills, Illinois
M2.9
131 km
6 km
Jun 10, 2013
4 km NNE of Virgil, Illinois
M2.6
130 km
5 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
534 tornadoes (EF0+) recorded within 100 km since 1950.
Strongest on record: EF5. Total: 46 fatalities, 998 injuries.
Date
Rating
Distance
Path
Fatalities
Jun 7, 1984
EF5
46 km
36.0 mi
9
Apr 9, 2015
EF4
93 km
30.1 mi
2
Jul 3, 1983
EF4
49 km
0.5 mi
0
Mar 29, 1981
EF4
99 km
5.1 mi
0
Apr 21, 1967
EF4
88 km
25.5 mi
24
Aug 7, 2021
EF3
93 km
9.4 mi
0
Jun 16, 2014
EF3
55 km
1.0 mi
0
Jan 7, 2008
EF3
88 km
13.2 mi
0
Aug 18, 2005
EF3
54 km
18.6 mi
1
Jun 19, 1993
EF3
75 km
14.0 mi
0
Jun 17, 1992
EF3
45 km
16.0 mi
0
May 8, 1988
EF3
29 km
16.0 mi
0
Aug 5, 1979
EF3
66 km
5.7 mi
0
Jun 4, 1975
EF3
91 km
2.3 mi
0
Jun 20, 1974
EF3
73 km
10.6 mi
1
Sep 9, 1970
EF3
66 km
4.7 mi
0
Aug 2, 1967
EF3
72 km
0.1 mi
2
Apr 16, 1967
EF3
7 km
27.8 mi
0
Jan 24, 1967
EF3
42 km
24.9 mi
0
Jan 24, 1967
EF3
59 km
7.4 mi
0
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
3 wildfires (100+ acres) recorded within 100 km.
Largest: 2018 BADGER RX BURNS (659 acres, 2018).
Year
Name
Acres Burned
Distance
2018
2018 BADGER RX BURNS
659
90 km
2019
2019 BADGER RX BURNS
627
90 km
2009
COLD SPRINGS
552
23 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
Month
Avg Temperature
Precipitation
Summary
January
19°F (-7°C)
1.1 in
Coldest, Driest
February
22°F (-6°C)
1.1 in
March
34°F (1°C)
2.3 in
April
47°F (8°C)
3.2 in
May
58°F (15°C)
3.5 in
June
68°F (20°C)
4.1 in
July
73°F (23°C)
3.9 in
Warmest
August
69°F (21°C)
4.2 in
Wettest
September
62°F (16°C)
3.9 in
October
50°F (10°C)
2.5 in
November
36°F (2°C)
2.3 in
December
23°F (-5°C)
1.7 in
South Wayne has a seasonal temperature swing of 54°F / from 19°F in January to 73°F in July. Total annual precipitation is 33.9 inches, with August being the wettest month (4.2") and January the driest (1.1").