December weather forecastThunder Bay, Canada

December

Weather in December

The weather in Thunder Bay in December is characterized by a full winter cloak. Temperatures fall significantly, and snowfall rises to 389mm (15.31"). This marks a return to the deep winter conditions experienced early in the year. The festive season in December brings a unique charm to the snowy Thunder Bay landscape, making it a winter wonderland.

Temperature

December's arrival in Thunder Bay comes with a decrease in the average high-temperature, moving from a cold 1.4°C (34.5°F) in November to a freezing cold -5.5°C (22.1°F). Thunder Bay, in December, observes a steady average low-temperature of -16°C (3.2°F).

Rainfall

In Thunder Bay, Canada, in December, it is raining for 1.2 days, with typically 6mm (0.24") of accumulated precipitation. In Thunder Bay, during the entire year, the rain falls for 92.6 days and collects up to 547mm (21.54") of precipitation.

Snowfall

January through May, September through December are months with snowfall in Thunder Bay. December is the month with the most snowfall. Snow falls for 13.9 days and accumulates 389mm (15.31") of snow.

Sea temperature

In December, the average sea temperature is 4°C (39.2°F).
Note: When swimming, this is deemed life-endangering and extremely risky. The painful cold water instigates fast-paced hyperventilation. Wearing a specialized swimsuit is necessary to lessen thermal harm.

Daylight

With an average of 8h and 24min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 8:28 am and sunset at 5:04 pm. On the last day of December, sunrise is at 8:48 am and sunset at 5:12 pm EST.

Sunshine

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

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: A maximum high UV index of 1 in December translates into the following recommendations:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.

Updated: Feb 5, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

The average high-temperature, in December, in Thunder Bay, is -5.5°C (22.1°F), while the average low-temperature is -16°C (3.2°F).

In Thunder Bay, in December, during 1.2 rainfall days, 6mm (0.24") of precipitation is typically accumulated.

The month with the most snowfall in Thunder Bay, Canada, is December, when snow falls for 13.9 days and typically aggregates up to 389mm (15.31") of snow.

In Thunder Bay, Canada, in December, snow falls for 13.9 days, with typically accumulated 389mm (15.31") of snow.

In December, the average sea temperature is 4°C (39.2°F). For swimming, this is considered extremely cold, dangerous, and life-threatening. Unless suitably protected with insulated waterproof clothing, hypothermia quickly occurs.

December has the shortest days of the year in Thunder Bay, with an average of 8h and 24min of daylight.

In Thunder Bay, Canada, the average day length in December is 8h and 24min.

In December, on the first day of the month, sunrise is at 8:28 am and sunset at 5:04 pm. On the last day of the month, in Thunder Bay, Canada, sunrise is at 8:48 am and sunset at 5:12 pm EST.

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

The average sunshine duration in December is 2.9h.

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

The average daily maximum UV index in December in Thunder Bay is 1. A UV Index estimate of 2, and below, represents a minimal hazard to health from exposure to the Sun's UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A S O N December

Nov

December

Jan

Average high temperature

1.4°C

-5.5°C

-8°C

Average low temperature

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

9.7

13.9

12.9

Average sea temperature

Average daylight

Average sunshine

Average UV index

Average temperature in December
Thunder Bay, Canada

Average high temperature in December: -5.5°C

The warmest month (with the highest average high temperature) is July (24.3°C).
The month with the lowest average high temperature is January (-8°C).

Average low temperature in December: -16°C

The month with the highest average low temperature is July (11.1°C).
The coldest month (with the lowest average low temperature) is January (-20.6°C).

Average rainfall in December
Thunder Bay, Canada

Average rainfall in December: 6.2mm

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

Average rainfall days in December
Thunder Bay, Canada

Average rainfall days in December: 1.2 days

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

Average snowfall in December
Thunder Bay, Canada

Average snowfall in December: 389mm

The month with the highest snowfall is December (389mm).
The months with the least snowfall are June, July and August (0mm).

Average snowfall days in December
Thunder Bay, Canada

Average snowfall days in December: 13.9 days

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

Average sea temperature in December
Thunder Bay, Canada

Average sea temperature in December: 4°C

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

Average daylight in December /
Average sunshine in December
Thunder Bay, Canada

Average daylight in December: 8h and 24min

The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).

Average sunshine in December: 2h and 54min

The month with the most sunshine is June (Average sunshine: 8h and 42min).
The months with the least sunshine are November and December (Average sunshine: 2h and 54min).

Average UV index in December
Thunder Bay, Canada

Average UV index in December: 1

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 1).