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January Weather in Thunder Bay, Canada

Last updated: June 18, 2025

In January, the average temperature in Thunder Bay, Canada hovers around -13°C (9°F). Expect chilly extremes, with minimums plummeting to -36°C (-33°F) and maximums reaching up to 3°C (37°F). Precipitation during this month averages 30 mm (1.2 in) over about 6 days, while the air remains notably humid, with an average humidity of 95%.

January Temperature in Thunder Bay

In January in Thunder Bay, the average temperature is -13°C (9°F), with maximums reaching 3°C (37°F) and minimums dropping as low as -36°C (-33°F). Travelers should be prepared for extreme cold conditions during this time.

January Weather in Thunder Bay: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Thunder Bay, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Thunder Bay, January typically has an average temperature of -13°C (9°F), with highs reaching up to 3°C (37°F) and lows dropping to around -36°C (-33°F).
JanFebMarAprMayJunJulAugSepOctNovDec9923334758666355432716
Data source: Temperature data for Thunder Bay generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Thunder Bay

In Thunder Bay in January, the total precipitation amount is 30 mm (1.2 in) spread across 6 days.

January Precipitation Trends in Thunder Bay

The chart displays monthly precipitation patterns in Thunder Bay, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Thunder Bay, January typically receives around 30 mm (1.2 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec303531585258827798875255
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Thunder Bay

In Thunder Bay in January, humidity is 95%. With an average temperature of -13°C (9°F), this humidity feels like an icy blanket wrapping around you, making it difficult to stay warm while traveling.

January Average Humidity in Thunder Bay

This chart illustrates the average monthly humidity levels in Thunder Bay, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Thunder Bay is approximately 95%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec95%94%92%90%79%71%70%72%76%82%87%94%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Thunder Bay

In Thunder Bay in January, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Thunder Bay, you can visit Hourly UV Index in Thunder Bay.

Maximum UV Index Levels in Thunder Bay for January

The chart shows the monthly maximum UV Index (UVI) for Thunder Bay in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Thunder Bay typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235789887421
Data source: Thunder Bay January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How January Weather in Thunder Bay Compares to Other Months

Weather in Thunder Bay varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Thunder Bay, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Thunder Bay, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-13°C (9°F)30 mm (1.2 inches)95%low
February Weather-13°C (9°F)35 mm (1.4 inches)94%moderate
March Weather-5°C (23°F)31 mm (1.2 inches)92%moderate
April Weather1°C (33°F)58 mm (2.3 inches)90%high
May Weather8°C (47°F)52 mm (2.0 inches)78%very high
June Weather14°C (58°F)58 mm (2.3 inches)71%very high
July Weather19°C (66°F)82 mm (3.2 inches)70%very high
August Weather17°C (63°F)77 mm (3.0 inches)72%very high
September Weather13°C (55°F)98 mm (3.9 inches)76%high
October Weather6°C (43°F)87 mm (3.4 inches)82%moderate
November Weather-3°C (27°F)51 mm (2.0 inches)87%low
December Weather-9°C (16°F)55 mm (2.2 inches)94%low

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