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January Weather in Ontario, United States

Last updated: June 24, 2025

In Ontario, United States, the average temperature in January hovers around -2°C (29°F), with extremes ranging from a chilly -17°C (2°F) to a milder 15°C (59°F). Expect 94 mm (3.7 in) of precipitation spread over 15 days, contributing to a rather high average humidity of 90%. Be prepared for a month where the cold meets a damp atmosphere!

January Temperature in Ontario

In January in Ontario, the average temperature is -2°C (29°F). The maximum can reach 15°C (59°F), while the minimum can drop as low as -17°C (2°F). Travelers should be prepared for a wide range of temperatures, layering clothing accordingly to stay comfortable during their visit.

January Weather in Ontario: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Ontario, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ontario, January typically has an average temperature of -2°C (29°F), with highs reaching up to 15°C (59°F) and lows dropping to around -17°C (2°F).
JanFebMarAprMayJunJulAugSepOctNovDec283035445364727266554134
Data source: Temperature data for Ontario 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 Ontario

In Ontario in January, the precipitation amount is 94 mm (3.7 in) over a span of 15 days.

January Precipitation Trends in Ontario

The chart displays monthly precipitation patterns in Ontario, 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 Ontario, January typically receives around 94 mm (3.7 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec9494851241108014910383164110113
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Ontario

In Ontario in January, humidity is 90%. With an average temperature of -2°C (29°F), this humidity feels like an icy breath enveloping you, making every step outdoors feel even colder and more biting, while also creating a heavy, wet atmosphere that can dampen your spirits for traveling.

January Average Humidity in Ontario

This chart illustrates the average monthly humidity levels in Ontario, 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 Ontario is approximately 90%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%90%87%88%82%79%78%76%78%84%89%86%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Ontario

In Ontario 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 Ontario, you can visit Hourly UV Index in Ontario.

Maximum UV Index Levels in Ontario for January

The chart shows the monthly maximum UV Index (UVI) for Ontario 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 Ontario typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24681010997532
Data source: Ontario 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 Ontario Compares to Other Months

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

This table compares monthly weather conditions in Ontario, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)94 mm (3.7 inches)90%low
February Weather-1°C (30°F)94 mm (3.7 inches)90%moderate
March Weather2°C (35°F)85 mm (3.3 inches)87%high
April Weather6°C (44°F)124 mm (4.9 inches)88%very high
May Weather12°C (54°F)110 mm (4.3 inches)82%very high
June Weather18°C (64°F)80 mm (3.1 inches)79%very high
July Weather22°C (72°F)149 mm (5.9 inches)78%very high
August Weather22°C (72°F)103 mm (4.1 inches)76%very high
September Weather19°C (66°F)83 mm (3.3 inches)78%high
October Weather13°C (56°F)164 mm (6.5 inches)84%moderate
November Weather5°C (42°F)110 mm (4.3 inches)89%moderate
December Weather1°C (34°F)113 mm (4.4 inches)86%low

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