March Weather in Ontario, United States

Last updated: June 24, 2025

In March, the average temperature in Ontario, United States hovers around 2°C (35°F). While you might experience lows of -25°C (-13°F), sunny days could bring highs of 19°C (67°F). Be prepared for occasional rainfall, as 59 mm (2.3 in) of precipitation often falls over 9 days. With an average humidity of 84%, don’t forget to dress comfortably for the damp weather!

March Temperature in Ontario

In March in Ontario, the average temperature is 2°C (35°F). Maximum temperatures can reach 19°C (67°F), while the minimum can drop as low as -25°C (-13°F). Be prepared for a wide range of temperatures when traveling to Ontario during this time.

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

The chart illustrates March 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, March typically has an average temperature of 2°C (35°F), with highs reaching up to 19°C (67°F) and lows dropping to around -25°C (-13°F).

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

March Precipitation in Ontario

In Ontario in March, the precipitation amount is 59 mm (2.3 in) over the course of 9 days.

March Precipitation Trends in Ontario

The chart displays monthly precipitation patterns in Ontario, with values for each month alongside March’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how March’s conditions compare to those of other months. In Ontario, March typically receives around 59 mm (2.3 inches) of precipitation spread over approximately 9 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

March Humidity in Ontario

In Ontario in March, humidity is 84%. With an average temperature of 2°C (35°F), this humidity feels like an uncomfortable chill that penetrates your bones, making outdoor travel quite brisk and uninviting.

March Average Humidity in Ontario

This chart illustrates the average monthly humidity levels in Ontario, with March’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In March, average humidity in Ontario is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for March generated using information from the Copernicus Climate Change Service.

March UV Index in Ontario

In Ontario in March, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Ontario.

Maximum UV Index Levels in Ontario for March

The chart shows the monthly maximum UV Index (UVI) for Ontario in March, 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 March, the maximum UV index in Ontario typically reaches 5, which falls under the moderate exposure category.

Data source: Ontario March 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 March 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 March’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 March’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-7°C (20°F)	40 mm (1.6 inches)	84%	low
February Weather	-6°C (21°F)	54 mm (2.1 inches)	85%	moderate
March Weather	2°C (35°F)	59 mm (2.3 inches)	84%	moderate
April Weather	7°C (45°F)	91 mm (3.6 inches)	83%	very high
May Weather	15°C (59°F)	141 mm (5.5 inches)	75%	very high
June Weather	21°C (70°F)	121 mm (4.8 inches)	79%	very high
July Weather	23°C (74°F)	110 mm (4.3 inches)	75%	very high
August Weather	21°C (70°F)	117 mm (4.6 inches)	69%	very high
September Weather	18°C (64°F)	112 mm (4.4 inches)	74%	very high
October Weather	10°C (50°F)	115 mm (4.5 inches)	79%	moderate
November Weather	2°C (35°F)	52 mm (2.0 inches)	88%	moderate
December Weather	-3°C (27°F)	46 mm (1.8 inches)	82%	low