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). Expect chilly conditions with minimum temperatures dropping to -23°C (-9°F) and a potential high of 20°C (69°F). The region experiences about 81 mm (3.2 in) of precipitation over 10 days, contributing to an average humidity of a brisk 88%. Prepare for a cold and damp month ahead!

January Temperature in Ontario

In January in Ontario, the average temperature is -2°C (29°F). Maximums can reach 20°C (69°F), while minimums can drop as low as -23°C (-9°F). Travelers should be prepared for a wide range of temperatures, making it essential to pack for both warmth and mild weather.

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 20°C (69°F) and lows dropping to around -23°C (-9°F).

Data source: Temperature data for Ontario generated using information from the Copernicus Climate Change Service.

January Precipitation in Ontario

In Ontario in January, the precipitation amount is 81 mm (3.2 in) over a span of 10 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 81 mm (3.2 inches) of precipitation spread over approximately 10 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Ontario

In Ontario in January, humidity is 88%. With an average temperature of -2°C (29°F), this humidity feels like a biting chill in the air that penetrates layers of clothing, making outdoor activities challenging and potentially uncomfortable for travelers.

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 88%, offering insight into how humid the weather typically is during this month.

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 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Ontario, you can check the information here.

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 3, which falls under the moderate exposure category.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	81 mm (3.2 inches)	88%	moderate
February Weather	0°C (32°F)	98 mm (3.8 inches)	87%	moderate
March Weather	5°C (40°F)	103 mm (4.1 inches)	87%	high
April Weather	10°C (50°F)	130 mm (5.1 inches)	87%	very high
May Weather	17°C (62°F)	126 mm (5.0 inches)	81%	very high
June Weather	21°C (71°F)	141 mm (5.5 inches)	82%	very high
July Weather	24°C (75°F)	123 mm (4.8 inches)	81%	very high
August Weather	22°C (72°F)	89 mm (3.5 inches)	78%	very high
September Weather	20°C (67°F)	80 mm (3.2 inches)	78%	very high
October Weather	14°C (57°F)	98 mm (3.9 inches)	82%	high
November Weather	5°C (41°F)	92 mm (3.6 inches)	89%	moderate
December Weather	1°C (35°F)	92 mm (3.6 inches)	86%	low