Thunder Bay
Canada
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
Thunder Bay, Canada

January, like December, is a freezing cold winter month in Thunder Bay, Canada, with temperature in the range of an average low of -20.6°C (-5.1°F) and an average high of -8°C (17.6°F). January is the coldest month, with an average high-temperature of -8°C (17.6°F) and an average low-temperature of -20.6°C (-5.1°F). Weather in January »
February, the last month of the winter, in Thunder Bay, is also a subzero cold month, with average temperature varying between -17.7°C (0.1°F) and -5°C (23°F). In February, the average high-temperature marginally rises, from -8°C (17.6°F) in January, to a still subzero cold -5°C (23°F). Weather in February »

March, the first month of the spring, in Thunder Bay, is a wintry month, with average temperature varying between -10.7°C (12.7°F) and 0.6°C (33.1°F). In Thunder Bay, the average high-temperature increases, from a freezing cold -5°C (23°F) in February, to a wintry 0.6°C (33.1°F). Weather in March »

April is a chilly spring month in Thunder Bay, Canada, with average temperature fluctuating between -3.2°C (26.2°F) and 9.2°C (48.6°F). In April, the average high-temperature increases considerably, from a wintry 0.6°C (33.1°F) in March, to a chilly 9.2°C (48.6°F). Weather in April »

The last month of the spring, May, is an enjoyable month in Thunder Bay, Canada, with average temperature ranging between min 2.2°C (36°F) and max 16.2°C (61.2°F). In Thunder Bay, the average high-temperature rises, from a frosty 9.2°C (48.6°F) in April, to a comfortable 16.2°C (61.2°F). Weather in May »

June, the first month of the summer, in Thunder Bay, is an agreeable month, with average temperature ranging between max 20.6°C (69.1°F) and min 7.1°C (44.8°F). In June, the average high-temperature marginally rises, from an enjoyable 16.2°C (61.2°F) in May, to an agreeable 20.6°C (69.1°F). Weather in June »

July is a moderately hot summer month in Thunder Bay, Canada, with temperature in the range of an average high of 24.3°C (75.7°F) and an average low of 11.1°C (52°F). With an average high-temperature of 24.3°C (75.7°F) and an average low-temperature of 11.1°C (52°F), July is the warmest month. Weather in July »

August, the last month of the summer, in Thunder Bay, is also a moderately hot month, with average temperature fluctuating between 23.3°C (73.9°F) and 10.4°C (50.7°F). In August, the average high-temperature is essentially the same as in July - a still warm 23.3°C (73.9°F). Weather in August »

The first month of the autumn, September, is still a comfortable month in Thunder Bay, Canada, with average temperature varying between 17.7°C (63.9°F) and 5.5°C (41.9°F). In September, the average high-temperature decreases, from a moderately hot 23.3°C (73.9°F) in August, to an enjoyable 17.7°C (63.9°F). Weather in September »

October, like September, is a frosty autumn month in Thunder Bay, Canada, with average temperature ranging between max 9.9°C (49.8°F) and min -0.9°C (30.4°F). In Thunder Bay, the average high-temperature decreases, from a comfortable 17.7°C (63.9°F) in September, to a frosty 9.9°C (49.8°F). Weather in October »

November, the last month of the autumn, in Thunder Bay, is also a wintry month, with temperature in the range of an average low of -7.7°C (18.1°F) and an average high of 1.4°C (34.5°F). In Thunder Bay, the average high-temperature in November significantly decreases, from a chilly 9.9°C (49.8°F) in October, to a cold 1.4°C (34.5°F). Weather in November »

The first month of the winter, December, is also a subzero cold month in Thunder Bay, Canada, with average temperature varying between -5.5°C (22.1°F) and -16°C (3.2°F). In December, the average high-temperature drops, from a cold 1.4°C (34.5°F) in November, to a freezing cold -5.5°C (22.1°F). Weather in December »

What is the coldest month in Thunder Bay?

With an average high-temperature of -8°C (17.6°F) and an average low-temperature of -20.6°C (-5.1°F), January is the coldest month in Thunder Bay.

How many days does it rain in Thunder Bay?

Throughout the year, in Thunder Bay, there are 92.6 rainfall days, and 546.5mm (21.5") of precipitation is accumulated.

What is the driest month in Thunder Bay?

The month with the least rainfall in Thunder Bay, Canada, is January when the rain falls for 0.6 days and typically collects 0.4mm (0") of precipitation.

When does it snow in Thunder Bay?

January through May, September through December are months with snowfall in Thunder Bay, Canada.

How many days does it snow in Thunder Bay?

Throughout the year, there are 62.7 snowfall days, and 1631mm (64.2") of snow is accumulated.

What months are the sea coldest in Thunder Bay?

January through April, with an average sea temperature of 2°C (35.6°F), are months with the coldest seawater in Thunder Bay, Canada. For swimming, this is considered life-threatening and very dangerous. The water feels painfully cold, and hyperventilation quickly occurs. A specialized swimsuit is mandatory to reduce thermal damage.

What are the months with the lowest UV index in Thunder Bay?

Months with the lowest UV index in Thunder Bay, Canada, are January, February, November and December, with an average maximum UV index of 1.

When are the longest days in Thunder Bay?

June has the longest days of the year, with an average of 16h of daylight.

What month has the most sunshine in Thunder Bay?

The month with the most sunshine is June, with an average of 8.7h of sunshine.

What are the months with the highest UV index in Thunder Bay?

Months with the highest UV index in Thunder Bay are June and July, with an average maximum UV index of 7.

What is the warmest month in Thunder Bay?

July is the warmest month in Thunder Bay, with an average high-temperature of 24.3°C (75.7°F) and an average low-temperature of 11.1°C (52°F).

What is the wettest month in Thunder Bay?

August is the month with the most rainfall. Rain falls for 12.3 days and accumulates 89.5mm (3.5") of precipitation.

What are the months with the warmest sea water in Thunder Bay?

Months with the warmest seawater are August and September, with an average sea temperature of 13°C (55.4°F). At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 13°C (55.4°F) is not comfortable.

What is the month with the least sunshine in Thunder Bay?

November and December, with an average of 2.9h of sunshine, are months with the least sunshine in Thunder Bay.

When does it snow the most in Thunder Bay?

The month with the most snowfall in Thunder Bay is December when snow falls for 13.9 days and typically aggregates up to 389mm (15.3") of snow.

What is the month with the shortest days in Thunder Bay?

With an average of 8.4h of daylight, December has the shortest days of the year.
Average temperature - Thunder Bay, Canada
Average rainfall - Thunder Bay, Canada

The wettest month (with the highest rainfall) is August (89.5mm).
The driest month (with the lowest rainfall) is January (0.4mm).

Average rainfall days - Thunder Bay, Canada

The month with the highest number of rainy days is June (13.8 days).
The month with the lowest number of rainy days is January (0.6 days).

Average snowfall - Thunder Bay, Canada
Average snowfall days - Thunder Bay, Canada

The month with the highest number of snowfall days is December (13.9 days).
Months with the lowest number of snowfall days are June, July and August (0 days).

Average sea temperature - Thunder Bay, Canada

Best months for swimming (with the highest average sea temperature) are August and September (13°C).
Coldest months (with the lowest average sea temperature) are January, February, March and April (2°C).

Average daylight / Average sunshine - Thunder Bay, Canada

The month with the longest days is June (Average daylight: 16h).
The month with shortest days is December (Average daylight: 8.4h).

The month with most sunshine is June (Average sunshine: 8.7h).
Months with least sunshine are November and December (Average sunshine: 2.9).

Average UV index - Thunder Bay, Canada