Thunder Bay weather by month

Check out Thunder Bay weather averages by month. Compare detailed monthly climate statistics including temperature, rainfall and sunshine figures.

Temperature
Rainfall
Sunshine & UV index

Temperature in Thunder Bay (°F)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Max temperature (daytime)	16	21	32	46	59	68	75	72	63	50	36	21
Min temperature (night-time)	-6	-2	10	27	36	45	52	50	43	34	19	3
Heat & Humidity	0	0	0	0	0	0	0	0	0	0	0	0
Sea temperature	36	36	36	36	37	39	45	55	55	46	41	39

Note: 0 = None, L = Low, M = Moderate, H = High, VH = Very high, E = Extreme

Sunshine & UV index in Thunder Bay

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Daily hours of sunshine	4	5	5	7	8	9	10	8	5	4	3	3
Daily hours of daylight	9	10	12	14	15	16	16	14	13	11	9	8
UV Index (Maximum)	1	1	3	4	6	7	7	6	5	2	1	1

Rainfall in Thunder Bay

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Number of days with some rain	11	9	10	9	11	13	12	13	13	11	10	11
Average monthly rainfall (inches)	1.5	1.1	1.7	1.8	2.8	3.2	3.2	3.5	3.5	2.4	1.9	1.8

More about Thunder Bay

Thunder Bay by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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The climate guide for Ontario (Thunder Bay) shows long term monthly weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

What's the climate like in Thunder Bay?

Thunder Bay has a cold climate with warm summers and some rainfall in all months.

Thunder Bay weather in January

Expect daytime maximum temperatures of 16°F in Thunder Bay, Ontario in January based on long-term weather averages. There are 4 hours of sunshine per day on average with 11 days with some rainfall, which might fall as snow.

16
16°F max day temperature
4
4 hours of sunshine per day
11
11 days with some rainfall
-6
-6°F min night temperature
9
9 hours of daylight per day
0
No heat & humidity
1.5
1.5 inches of monthly rainfall
1
1 (Low) UV index
36
36°F sea temperature

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Thunder Bay weather in February

Expect daytime maximum temperatures of 21°F in Thunder Bay, Ontario in February based on long-term weather averages. There are 5 hours of sunshine per day on average, which might fall as snow.

21
21°F max day temperature
5
5 hours of sunshine per day
9
9 days with some rainfall
-2
-2°F min night temperature
10
10 hours of daylight per day
0
No heat & humidity
1.1
1.1 inches of monthly rainfall
1
1 (Low) UV index
36
36°F sea temperature

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Thunder Bay weather in March

Expect daytime maximum temperatures of 32°F in Thunder Bay, Ontario in March based on long-term weather averages. There are 5 hours of sunshine per day on average with 10 days with some rainfall and typically 1.7 inches of rainfall in the month, which might fall as snow.

32
32°F max day temperature
5
5 hours of sunshine per day
10
10 days with some rainfall
10
10°F min night temperature
12
12 hours of daylight per day
0
No heat & humidity
1.7
1.7 inches of monthly rainfall
3
3 (Moderate) UV index
36
36°F sea temperature

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Thunder Bay weather in April

Expect daytime maximum temperatures of 46°F in Thunder Bay, Ontario in April based on long-term weather averages. There are 7 hours of sunshine per day on average with typically 1.8 inches of rainfall in the month.

46
46°F max day temperature
7
7 hours of sunshine per day
9
9 days with some rainfall
27
27°F min night temperature
14
14 hours of daylight per day
0
No heat & humidity
1.8
1.8 inches of monthly rainfall
4
4 (Moderate) UV index
36
36°F sea temperature

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Thunder Bay weather in May

Expect daytime maximum temperatures of 59°F in Thunder Bay, Ontario in May based on long-term weather averages. There are 8 hours of sunshine per day on average with 11 days with some rainfall and typically 2.8 inches of rainfall in the month.

59
59°F max day temperature
8
8 hours of sunshine per day
11
11 days with some rainfall
36
36°F min night temperature
15
15 hours of daylight per day
0
No heat & humidity
2.8
2.8 inches of monthly rainfall
6
6 (High) UV index
37
37°F sea temperature

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Thunder Bay weather in June

Expect daytime maximum temperatures of 68°F in Thunder Bay, Ontario in June based on long-term weather averages. There are 9 hours of sunshine per day on average with 13 days with some rainfall and typically 3.2 inches of rainfall in the month.

68
68°F max day temperature
9
9 hours of sunshine per day
13
13 days with some rainfall
45
45°F min night temperature
16
16 hours of daylight per day
0
No heat & humidity
3.2
3.2 inches of monthly rainfall
7
7 (High) UV index
39
39°F sea temperature

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Thunder Bay weather in July

Expect daytime maximum temperatures of 75°F in Thunder Bay, Ontario in July based on long-term weather averages. There are 10 hours of sunshine per day on average with 12 days with some rainfall and typically 3.2 inches of rainfall in the month.

75
75°F max day temperature
10
10 hours of sunshine per day
12
12 days with some rainfall
52
52°F min night temperature
16
16 hours of daylight per day
0
No heat & humidity
3.2
3.2 inches of monthly rainfall
7
7 (High) UV index
45
45°F sea temperature

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Thunder Bay weather in August

Expect daytime maximum temperatures of 72°F in Thunder Bay, Ontario in August based on long-term weather averages. There are 8 hours of sunshine per day on average with 13 days with some rainfall and typically 3.5 inches of rainfall in the month.

72
72°F max day temperature
8
8 hours of sunshine per day
13
13 days with some rainfall
50
50°F min night temperature
14
14 hours of daylight per day
0
No heat & humidity
3.5
3.5 inches of monthly rainfall
6
6 (High) UV index
55
55°F sea temperature

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Thunder Bay weather in September

Expect daytime maximum temperatures of 63°F in Thunder Bay, Ontario in September based on long-term weather averages. There are 5 hours of sunshine per day on average with 13 days with some rainfall and typically 3.5 inches of rainfall in the month.

63
63°F max day temperature
5
5 hours of sunshine per day
13
13 days with some rainfall
43
43°F min night temperature
13
13 hours of daylight per day
0
No heat & humidity
3.5
3.5 inches of monthly rainfall
5
5 (Moderate) UV index
55
55°F sea temperature

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Thunder Bay weather in October

Expect daytime maximum temperatures of 50°F in Thunder Bay, Ontario in October based on long-term weather averages. There are 4 hours of sunshine per day on average with 11 days with some rainfall and typically 2.4 inches of rainfall in the month.

50
50°F max day temperature
4
4 hours of sunshine per day
11
11 days with some rainfall
34
34°F min night temperature
11
11 hours of daylight per day
0
No heat & humidity
2.4
2.4 inches of monthly rainfall
2
2 (Low) UV index
46
46°F sea temperature

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Thunder Bay weather in November

Expect daytime maximum temperatures of 36°F in Thunder Bay, Ontario in November based on long-term weather averages. There are 3 hours of sunshine per day on average with 10 days with some rainfall and typically 1.9 inches of rainfall in the month, which might fall as snow.

36
36°F max day temperature
3
3 hours of sunshine per day
10
10 days with some rainfall
19
19°F min night temperature
9
9 hours of daylight per day
0
No heat & humidity
1.9
1.9 inches of monthly rainfall
1
1 (Low) UV index
41
41°F sea temperature

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Thunder Bay weather in December

Expect daytime maximum temperatures of 21°F in Thunder Bay, Ontario in December based on long-term weather averages. There are 3 hours of sunshine per day on average with 11 days with some rainfall and typically 1.8 inches of rainfall in the month, which might fall as snow.

21
21°F max day temperature
3
3 hours of sunshine per day
11
11 days with some rainfall
3
3°F min night temperature
8
8 hours of daylight per day
0
No heat & humidity
1.8
1.8 inches of monthly rainfall
1
1 (Low) UV index
39
39°F sea temperature

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