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St. Thomas September Weather

Averages and records for weather in St. Thomas, Ontario in the month of September.

Typical St. Thomas September Weather 1991–2020
Average daily high	22.3 °C
Average daily low	11.1 °C
Average monthly precipitation	8.6 cm
Average monthly snow	none
Daily chance of precipitation	36.5%
Daily chance of snow	0%

St. Thomas September Weather Records 1882–2024
Highest temperature	35.6 °C	September 2, 1953
Lowest temperature	-2.8 °C	September 29, 1942
Highest daily low	23.5 °C	September 2, 2018
Lowest daily high	7.2 °C	September 28, 1967
Hottest average high temperature	25.1 °C	2002
Coldest average high temperature	18.3 °C	1975
Most daily precipitation	9.0 cm	September 16, 1983
Most monthly precipitation	21.6 cm	1977
Most daily snow	none	-
Most monthly snow	none	-

Note: Daily averages are a moving average which includes 14 days before and after

Day	Average (°C)		Record (°C)
Day	High	Low	High	Low
September 1	24.9	13.6	32.8	3.3
September 2	24.7	13.5	35.6	3.3
September 3	24.6	13.4	34.4	1.7
September 4	24.5	13.2	32.8	3.3
September 5	24.4	13.0	31.7	3.3
September 6	24.3	12.9	32.2	3.3
September 7	24.1	12.8	31.0	2.2
September 8	24.0	12.6	35.6	1.0
September 9	23.8	12.4	33.0	2.2
September 10	23.6	12.2	32.8	3.9
September 11	23.4	12.0	35.0	1.7
September 12	23.2	11.8	35.0	-0.6
September 13	23.0	11.7	33.9	1.1
September 14	22.8	11.5	31.7	1.1
September 15	22.6	11.3	32.2	2.8
September 16	22.3	11.1	33.3	0.6
September 17	22.1	10.9	31.1	-1.7
September 18	21.9	10.7	31.7	-0.6
September 19	21.7	10.5	32.2	-0.6
September 20	21.5	10.4	31.1	-2.8
September 21	21.2	10.2	28.9	-1.1
September 22	20.9	9.9	30.0	0.0
September 23	20.7	9.7	31.5	-1.1
September 24	20.5	9.5	31.5	-1.1
September 25	20.3	9.4	30.0	-1.1
September 26	20.1	9.2	30.0	-1.7
September 27	19.9	9.0	29.5	-2.2
September 28	19.7	8.8	28.3	-2.0
September 29	19.5	8.6	28.0	-2.8
September 30	19.3	8.4	25.0	-1.7

Weather Station Details

Years	Station	Coordinates
1980–2024	St Thomas WPCP	location
1882–1980	St Thomas	location