Thunder Bay climate guide

Temperature in Thunder Bay (°C)

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max temperature (daytime)
-9°C maximum daytime temperature in January in Thunder Bay-9
-6°C maximum daytime temperature in February in Thunder Bay-6
0°C maximum daytime temperature in March in Thunder Bay0
8°C maximum daytime temperature in April in Thunder Bay8
15°C maximum daytime temperature in May in Thunder Bay15
20°C maximum daytime temperature in June in Thunder Bay20
24°C maximum daytime temperature in July in Thunder Bay24
22°C maximum daytime temperature in August in Thunder Bay22
17°C maximum daytime temperature in September in Thunder Bay17
10°C maximum daytime temperature in October in Thunder Bay10
2°C maximum daytime temperature in November in Thunder Bay2
-6°C maximum daytime temperature in December in Thunder Bay-6
Min temperature (night-time)
-21°C minimum night-time temperature in January in Thunder Bay-21
-19°C minimum night-time temperature in February in Thunder Bay-19
-12°C minimum night-time temperature in March in Thunder Bay-12
-3°C minimum night-time temperature in April in Thunder Bay-3
2°C minimum night-time temperature in May in Thunder Bay2
7°C minimum night-time temperature in June in Thunder Bay7
11°C minimum night-time temperature in July in Thunder Bay11
10°C minimum night-time temperature in August in Thunder Bay10
6°C minimum night-time temperature in September in Thunder Bay6
1°C minimum night-time temperature in October in Thunder Bay1
-7°C minimum night-time temperature in November in Thunder Bay-7
-16°C minimum night-time temperature in December in Thunder Bay-16
Sea temperature
2°C sea temperature in January in Thunder Bay2
2°C sea temperature in February in Thunder Bay2
2°C sea temperature in March in Thunder Bay2
2°C sea temperature in April in Thunder Bay2
3°C sea temperature in May in Thunder Bay3
4°C sea temperature in June in Thunder Bay4
7°C sea temperature in July in Thunder Bay7
13°C sea temperature in August in Thunder Bay13
13°C sea temperature in September in Thunder Bay13
8°C sea temperature in October in Thunder Bay8
5°C sea temperature in November in Thunder Bay5
4°C sea temperature in December in Thunder Bay4

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

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 (mm)
38 mm monthly rainfall in January in Thunder Bay38
27 mm monthly rainfall in February in Thunder Bay27
42 mm monthly rainfall in March in Thunder Bay42
45 mm monthly rainfall in April in Thunder Bay45
70 mm monthly rainfall in May in Thunder Bay70
82 mm monthly rainfall in June in Thunder Bay82
82 mm monthly rainfall in July in Thunder Bay82
88 mm monthly rainfall in August in Thunder Bay88
88 mm monthly rainfall in September in Thunder Bay88
60 mm monthly rainfall in October in Thunder Bay60
49 mm monthly rainfall in November in Thunder Bay49
45 mm monthly rainfall in December in Thunder Bay45

More climate for Thunder Bay

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

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

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More about Thunder Bay

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The climate guide for Thunder Bay, Ontario 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.

Metric (°C / mm)  |  Imperial (°F / inches)

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