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Thunder Bay May Weather

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

Typical Thunder Bay May Weather 1991–2020
Average daily high	16.0 °C
Average daily low	2.0 °C
Average monthly precipitation	7.3 cm
Daily chance of precipitation	45.7%

Thunder Bay May Weather Records 1941–2024
Highest temperature	35.2 °C	May 30, 1986
Lowest temperature	-8.9 °C	May 2, 1958
Highest daily low	16.4 °C	May 30, 1995
Lowest daily high	-4.4 °C	May 3, 1954
Hottest average high temperature	19.3 °C	1977
Coldest average high temperature	10.8 °C	1954
Most daily precipitation	9.1 cm	May 27, 2012
Most monthly precipitation	19.2 cm	2012

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

Day	Average (°C)		Record (°C)
Day	High	Low	High	Low
May 1	12.5	-1.1	25.0	-6.7
May 2	12.7	-0.9	28.7	-8.9
May 3	12.9	-0.8	27.9	-8.3
May 4	13.2	-0.7	32.6	-8.9
May 5	13.4	-0.5	25.6	-7.8
May 6	13.7	-0.3	28.6	-6.7
May 7	13.9	-0.1	30.6	-7.8
May 8	14.1	0.2	32.8	-7.2
May 9	14.3	0.4	30.0	-7.2
May 10	14.6	0.6	29.8	-6.7
May 11	14.8	0.9	30.3	-8.4
May 12	15.1	1.2	33.0	-7.9
May 13	15.4	1.4	27.2	-7.6
May 14	15.6	1.6	26.7	-5.6
May 15	15.9	1.8	31.9	-7.2
May 16	16.1	2.0	30.1	-6.7
May 17	16.3	2.2	30.0	-5.9
May 18	16.4	2.4	30.5	-6.3
May 19	16.6	2.6	30.6	-4.9
May 20	16.8	2.8	31.2	-5.6
May 21	16.9	2.9	32.5	-4.9
May 22	17.1	3.1	34.8	-4.4
May 23	17.3	3.3	29.5	-3.9
May 24	17.6	3.4	29.4	-5.6
May 25	17.8	3.6	30.9	-4.4
May 26	18.0	3.8	31.7	-3.0
May 27	18.2	4.0	30.6	-3.7
May 28	18.4	4.2	33.9	-4.6
May 29	18.6	4.4	34.2	-3.6
May 30	18.8	4.6	35.2	-3.7
May 31	19.0	4.8	31.4	-3.5

Weather Station Details

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