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Thunder Bay August Weather

Averages and records for weather in Thunder Bay, Ontario in the month of August.

Typical Thunder Bay August Weather 1991–2020
Average daily high	24.0 °C
Average daily low	10.0 °C
Average monthly precipitation	6.5 cm
Daily chance of precipitation	42.1%

Thunder Bay August Weather Records 1941–2024
Highest temperature	40.3 °C	August 7, 1983
Lowest temperature	-1.1 °C	August 29, 1976
Highest daily low	21.1 °C	August 24, 1947
Lowest daily high	9.4 °C	August 24, 1950
Hottest average high temperature	27.0 °C	1983
Coldest average high temperature	19.7 °C	1964
Most daily precipitation	8.7 cm	August 19, 1973
Most monthly precipitation	17.0 cm	1988

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

Day	Average (°C)		Record (°C)
Day	High	Low	High	Low
August 1	24.8	10.8	32.5	2.8
August 2	24.8	10.8	34.3	4.4
August 3	24.8	10.8	32.2	3.8
August 4	24.7	10.7	32.5	2.8
August 5	24.6	10.6	33.2	4.3
August 6	24.6	10.6	34.0	4.4
August 7	24.5	10.5	40.3	4.4
August 8	24.5	10.5	35.6	5.0
August 9	24.4	10.4	33.3	2.8
August 10	24.4	10.3	31.6	2.2
August 11	24.4	10.3	32.2	2.1
August 12	24.4	10.3	33.1	2.8
August 13	24.3	10.3	34.6	3.3
August 14	24.2	10.2	33.9	2.2
August 15	24.1	10.1	32.9	2.2
August 16	23.9	10.0	31.2	3.7
August 17	23.8	9.9	32.8	3.7
August 18	23.8	9.8	31.7	0.4
August 19	23.7	9.8	35.0	1.9
August 20	23.6	9.7	31.7	0.6
August 21	23.4	9.6	33.3	1.6
August 22	23.3	9.5	32.2	0.0
August 23	23.2	9.4	35.0	1.6
August 24	23.1	9.3	32.2	0.0
August 25	22.9	9.2	32.8	0.4
August 26	22.7	9.0	31.7	-0.6
August 27	22.5	8.9	33.9	1.1
August 28	22.4	8.8	31.7	1.7
August 29	22.3	8.7	33.9	-1.1
August 30	22.1	8.6	32.8	0.0
August 31	21.9	8.4	31.1	1.7

Weather Station Details

Years	Station	Coordinates
2004–2024	Thunder Bay CS	location
1941–2003	Thunder Bay A	location