Weather & Climate in St. Clair, ON

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

St. Clair experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 24°F in January while summers reach 73°F in July. The area gets 272 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 35.3 inches. The area receives 9.5 inches of snow annually. Air quality is rated Good with a median AQI of 27 / among the cleanest air in the country. 90% of days have good air quality. The city sits at an elevation of 591 feet.

Temperature

24°F Jan (-5°C) 73°F Jul (23°C)

Annual Average	49.0°F
	9% below US avg
January Average	24°F (-5°C)
July Average	73°F (23°C)
Sunny Days	272 days/yr

Geography

Elevation	591 ft (180 m)
Area	238.8 sq mi (618.6 km²)
Population Density	61/sq mi
Coordinates	42.3192°N, 82.8578°W
Timezone	America/Toronto

Precipitation & Snow

Annual Rainfall 35.3"

7% below US avg

Snowfall 9.5"

Wettest Month (Sep) 3.66"

Driest Month (Jan) 1.93"

Air Quality

AQI Median	27.0
Rating	Good
Good Days %	89.5%

Earthquake History

29 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.0.

Jun 10, 2019	1 km NW of Timberlake, Ohio	M4.0	136 km	2 km
Jun 30, 2003	6 km NW of Perry, Ohio	M3.6	149 km	5 km
Mar 15, 1992	15 km NW of North Perry, Ohio	M3.5	141 km	5 km
Jun 20, 2006	9 km WNW of North Perry, Ohio	M3.5	145 km	5 km
Jan 26, 1991	1 km NNE of Mayfield Heights, Ohio	M3.4	145 km	5 km
Apr 20, 2018	Michigan	M3.4	26 km	3 km
Jul 1, 2013	5 km NNW of Fairport Harbor, Ohio	M3.2	142 km	5 km
Jan 9, 2008	6 km WNW of Mentor-on-the-Lake, Ohio	M3.1	136 km	5 km
Mar 11, 2006	8 km NNW of Mentor-on-the-Lake, Ohio	M3.1	135 km	5 km
Feb 23, 2011	18 km NE of Leamington, Canada	M3.0	40 km	5 km
Apr 12, 2007	11 km NW of Put-in-Bay, Ohio	M2.8	67 km	5 km
Sep 22, 1999	16 km NW of Mentor-on-the-Lake, Ohio	M2.8	127 km	18 km
Jan 4, 2022	3 km NW of Timberlake, Ohio	M2.8	135 km	5 km
Nov 25, 1998	1 km SSW of New London, Ohio	M2.7	144 km	5 km
Mar 8, 2013	5 km NNW of Timberlake, Ohio	M2.7	133 km	5 km
Apr 28, 2002	Ohio	M2.7	133 km	5 km
May 14, 2010	1 km ENE of Gibsonburg, Ohio	M2.7	110 km	5 km
May 14, 2017	18 km ENE of Leamington, Canada	M2.6	42 km	5 km
Jun 10, 2010	8 km NW of Mentor-on-the-Lake, Ohio	M2.6	133 km	5 km
Jan 6, 2006	10 km NW of Mentor-on-the-Lake, Ohio	M2.6	131 km	5 km

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

Tsunami History

1 tsunami recorded within 500 km. Highest wave on record: 1.5 m (5 ft).

Year	Location	Cause	Max Wave	Deaths	Distance
1952	LAKE HURON, MI	Avalanche	1.5 m	—	95 km

Source: NOAA/NCEI Historical Tsunami Database.

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	24°F (-5°C)	1.9 in	Coldest, Driest
February	26°F (-3°C)	2.0 in
March	36°F (2°C)	2.7 in
April	47°F (8°C)	3.2 in
May	59°F (15°C)	3.2 in
June	68°F (20°C)	3.3 in
July	73°F (23°C)	3.4 in	Warmest
August	71°F (22°C)	3.3 in
September	64°F (18°C)	3.7 in	Wettest
October	52°F (11°C)	2.6 in
November	41°F (5°C)	3.2 in
December	30°F (-1°C)	2.9 in

St. Clair has a seasonal temperature swing of 49°F / from 24°F in January to 73°F in July. Total annual precipitation is 35.3 inches, with September being the wettest month (3.7") and January the driest (1.9").

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