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 in Thunder Bay (°F)

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max temperature (daytime)
16°F maximum daytime temperature in January in Thunder Bay16
21°F maximum daytime temperature in February in Thunder Bay21
32°F maximum daytime temperature in March in Thunder Bay32
46°F maximum daytime temperature in April in Thunder Bay46
59°F maximum daytime temperature in May in Thunder Bay59
68°F maximum daytime temperature in June in Thunder Bay68
75°F maximum daytime temperature in July in Thunder Bay75
72°F maximum daytime temperature in August in Thunder Bay72
63°F maximum daytime temperature in September in Thunder Bay63
50°F maximum daytime temperature in October in Thunder Bay50
36°F maximum daytime temperature in November in Thunder Bay36
21°F maximum daytime temperature in December in Thunder Bay21
Min temperature (night-time)
-6°F minimum night-time temperature in January in Thunder Bay-6
-2°F minimum night-time temperature in February in Thunder Bay-2
10°F minimum night-time temperature in March in Thunder Bay10
27°F minimum night-time temperature in April in Thunder Bay27
36°F minimum night-time temperature in May in Thunder Bay36
45°F minimum night-time temperature in June in Thunder Bay45
52°F minimum night-time temperature in July in Thunder Bay52
50°F minimum night-time temperature in August in Thunder Bay50
43°F minimum night-time temperature in September in Thunder Bay43
34°F minimum night-time temperature in October in Thunder Bay34
19°F minimum night-time temperature in November in Thunder Bay19
3°F minimum night-time temperature in December in Thunder Bay3
Heat & Humidity
No heat & humidity in January in Thunder Bay0
No heat & humidity in February in Thunder Bay0
No heat & humidity in March in Thunder Bay0
No heat & humidity in April in Thunder Bay0
No heat & humidity in May in Thunder Bay0
No heat & humidity in June in Thunder Bay0
No heat & humidity in July in Thunder Bay0
No heat & humidity in August in Thunder Bay0
No heat & humidity in September in Thunder Bay0
No heat & humidity in October in Thunder Bay0
No heat & humidity in November in Thunder Bay0
No heat & humidity in December in Thunder Bay0
Sea temperature
36°F sea temperature in January in Thunder Bay36
36°F sea temperature in February in Thunder Bay36
36°F sea temperature in March in Thunder Bay36
36°F sea temperature in April in Thunder Bay36
37°F sea temperature in May in Thunder Bay37
39°F sea temperature in June in Thunder Bay39
45°F sea temperature in July in Thunder Bay45
55°F sea temperature in August in Thunder Bay55
55°F sea temperature in September in Thunder Bay55
46°F sea temperature in October in Thunder Bay46
41°F sea temperature in November in Thunder Bay41
39°F sea temperature in December in Thunder Bay39

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

Sunshine & Daylight in Thunder Bay

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daily hours of sunshine
Daily hours of daylight
9 hours of daylight per day in January in Thunder Bay9
10 hours of daylight per day in February in Thunder Bay10
12 hours of daylight per day in March in Thunder Bay12
14 hours of daylight per day in April in Thunder Bay14
15 hours of daylight per day in May in Thunder Bay15
16 hours of daylight per day in June in Thunder Bay16
16 hours of daylight per day in July in Thunder Bay16
14 hours of daylight per day in August in Thunder Bay14
13 hours of daylight per day in September in Thunder Bay13
11 hours of daylight per day in October in Thunder Bay11
9 hours of daylight per day in November in Thunder Bay9
8 hours of daylight per day in December in Thunder Bay8
UV Index (Maximum)
UV (maximum) index 1 (Low) in January in Thunder Bay1
UV (maximum) index 1 (Low) in February in Thunder Bay1
UV (maximum) index 3 (Moderate) in March in Thunder Bay3
UV (maximum) index 4 (Moderate) in April in Thunder Bay4
UV (maximum) index 6 (High) in May in Thunder Bay6
UV (maximum) index 7 (High) in June in Thunder Bay7
UV (maximum) index 7 (High) in July in Thunder Bay7
UV (maximum) index 6 (High) in August in Thunder Bay6
UV (maximum) index 5 (Moderate) in September in Thunder Bay5
UV (maximum) index 2 (Low) in October in Thunder Bay2
UV (maximum) index 1 (Low) in November in Thunder Bay1
UV (maximum) index 1 (Low) in December in Thunder Bay1

Rainfall in Thunder Bay

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Number of days with some rain
11 days with some rainfall in January in Thunder Bay11
9 days with some rainfall in February in Thunder Bay9
10 days with some rainfall in March in Thunder Bay10
9 days with some rainfall in April in Thunder Bay9
11 days with some rainfall in May in Thunder Bay11
13 days with some rainfall in June in Thunder Bay13
12 days with some rainfall in July in Thunder Bay12
13 days with some rainfall in August in Thunder Bay13
13 days with some rainfall in September in Thunder Bay13
11 days with some rainfall in October in Thunder Bay11
10 days with some rainfall in November in Thunder Bay10
11 days with some rainfall in December in Thunder Bay11
Average monthly rainfall (inches)
1.5 inches monthly rainfall in January in Thunder Bay1.5
1.1 inches monthly rainfall in February in Thunder Bay1.1
1.7 inches monthly rainfall in March in Thunder Bay1.7
1.8 inches monthly rainfall in April in Thunder Bay1.8
2.8 inches monthly rainfall in May in Thunder Bay2.8
3.2 inches monthly rainfall in June in Thunder Bay3.2
3.2 inches monthly rainfall in July in Thunder Bay3.2
3.5 inches monthly rainfall in August in Thunder Bay3.5
3.5 inches monthly rainfall in September in Thunder Bay3.5
2.4 inches monthly rainfall in October in Thunder Bay2.4
1.9 inches monthly rainfall in November in Thunder Bay1.9
1.8 inches monthly rainfall in December in Thunder Bay1.8

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.

Metric (°C)  |  Imperial (°F)

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More about Canada

Compare Thunder Bay with the USA

Below the Thunder Bay chart shows average maximum daytime temperature for Thunder Bay, Ontario, Canada and the USA (Washington).

Maximum daytime temperature (°F)

Thunder Bay, Ontario, Canada
USA (Washington)
41
45
32
55
46
66
59
75
68
84
75
88
72
86
63
79
50
68
36
57
46
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
16
21
21

Metric (°C)  |  Imperial (°F)

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