Weather & Climate in South Barrington, IL

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

South Barrington 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 246 sunny days per year, above the national average. Annual precipitation totals 40.4 inches. The area receives 38.5 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 855 feet.

Temperature

21°F Jan (-6°C) 72°F Jul (22°C)

Annual Average	48.0°F
	11% below US avg
January Average	21°F (-6°C)
July Average	72°F (22°C)
Sunny Days	246 days/yr

Geography

Elevation	855 ft (261 m)
Area	7.6 sq mi (19.7 km²)
Population Density	671/sq mi
Coordinates	42.0890°N, 88.1572°W
Timezone	America/Chicago
County	McHenry County County
Nearest Airport	Chicago O'Hare International (ORD) 15 miles away

Precipitation & Snow

Annual Rainfall 40.4"

6% above US avg

Snowfall 38.5"

Wettest Month (Aug) 4.17"

Driest Month (Feb) 1.34"

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	93 km	10 km
Feb 10, 2010	2 km NW of Lily Lake, Illinois	M3.8	31 km	10 km
Sep 2, 1999	8 km W of Amboy, Illinois	M3.5	113 km	5 km
Nov 4, 2013	1 km SSW of Lyons, Illinois	M3.2	42 km	1 km
Jul 15, 2024	2 km WNW of Somonauk, Illinois	M3.1	67 km	10 km
Mar 25, 2015	3 km WNW of Lake in the Hills, Illinois	M2.9	20 km	6 km
Jun 10, 2013	4 km NNE of Virgil, Illinois	M2.6	31 km	5 km
Mar 15, 2025	6 km W of Dwight, Illinois	M2.6	115 km	5 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

563 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 107 fatalities, 2,130 injuries.

Date	Rating	Distance	Path	Fatalities
Aug 28, 1990	EF5	48 km	16.4 mi	29
Apr 9, 2015	EF4	97 km	30.1 mi	2
Jun 29, 1979	EF4	64 km	5.4 mi	0
Jun 13, 1976	EF4	48 km	3.3 mi	2
Sep 28, 1972	EF4	32 km	5.2 mi	0
Apr 21, 1967	EF4	12 km	8.8 mi	1
Apr 21, 1967	EF4	54 km	15.0 mi	33
Apr 21, 1967	EF4	65 km	25.5 mi	24
Apr 11, 1965	EF4	23 km	9.1 mi	6
Jun 20, 2021	EF3	38 km	17.6 mi	0
Jun 22, 2015	EF3	89 km	16.3 mi	0
Jan 7, 2008	EF3	65 km	13.2 mi	0
Jan 7, 2008	EF3	53 km	10.8 mi	0
Mar 27, 1991	EF3	57 km	15.0 mi	0
Apr 27, 1984	EF3	62 km	9.0 mi	1
Jun 30, 1977	EF3	90 km	6.1 mi	0
Mar 12, 1976	EF3	54 km	22.6 mi	0
Oct 24, 1967	EF3	98 km	0.1 mi	0
Nov 12, 1965	EF3	82 km	4.1 mi	0
Jul 19, 1963	EF3	55 km	10.6 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	114 km

Source: NOAA/NCEI Historical Tsunami Database.

Wildfire History

11 wildfires (100+ acres) recorded within 100 km. Largest: UNNAMED (1,741 acres, 2019).

Year	Name	Acres Burned	Distance
2019	UNNAMED	1,741	79 km
2019	UNNAMED	1,664	80 km
2021	NORTHEAST PRAIRIE UNIT 3	978	81 km
2024	NORTHEAST PRAIRIE 3 RX	938	79 km
1986	OGDEN DUNS	863	94 km
2021	UNNAMED	738	79 km
2021	MIDDLE GRANT CREEK	700	80 km
2019	UNNAMED	698	79 km
2024	IBSP SOUTH F1 RX	690	45 km
2021	21-INDU TOLLESTON DUNES EAST	594	95 km
2017	UNNAMED	549	80 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	26°F (-3°C)	1.3 in	Driest
March	37°F (3°C)	2.5 in
April	48°F (9°C)	3.6 in
May	59°F (15°C)	3.5 in
June	69°F (20°C)	4.0 in
July	72°F (22°C)	3.9 in	Warmest
August	71°F (22°C)	4.2 in	Wettest
September	64°F (18°C)	3.7 in
October	52°F (11°C)	2.5 in
November	39°F (4°C)	2.9 in
December	27°F (-3°C)	2.2 in

South Barrington has a seasonal temperature swing of 51°F / from 21°F in January to 72°F in July. Total annual precipitation is 35.9 inches, with August being the wettest month (4.2") and February the driest (1.3").

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