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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). Expect minimum temperatures to dip as low as -12°C (10°F), while the maximum can reach a mild 19°C (67°F). During this month, anticipate approximately 85 mm (3.3 in) of precipitation over 13 days, with an average humidity of a damp 87%. Plan accordingly!

March Temperature in Ontario

In March in Ontario, the average temperature is 2°C (35°F). The maximum can reach 19°C (67°F), while the minimum can drop to -12°C (10°F). Be sure to pack accordingly for the varied temperatures during your travels.

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 -12°C (10°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.

March Precipitation in Ontario

In Ontario in March, the precipitation amount is 85 mm (3.3 in) spread over 13 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 85 mm (3.3 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec9494851241108014910383164110113
Data source: Precipitation data for March generated using information from the Copernicus Climate Change Service.
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March Humidity in Ontario

In Ontario in March, humidity is 87%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill that seeps into your bones, making traveling feel uncomfortable and heavy, as each breath carries a hint of the cold, moist air that lingers around you.

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 87%, 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 March generated using information from the Copernicus Climate Change Service.

March UV Index in Ontario

In Ontario in March, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Ontario, you can refer to this 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 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24681010997532
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.
 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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