April Weather in Ontario, United States

Last updated: June 24, 2025

In Ontario, United States, the average temperature in April is a brisk 7°C (45°F). Be prepared for a range: temperatures can dip to a chilling -10°C (15°F) or rise to a pleasant 26°C (80°F). Expect about 91 mm (3.6 in) of precipitation spread over 12 days, accompanied by an average humidity level of 83%.

April Temperature in Ontario

In April in Ontario, the average temperature is 7°C (45°F). Maximum temperatures can reach up to 26°C (80°F), while minimums can drop as low as -10°C (15°F). Be prepared for a wide range of temperatures, making it essential to pack layers for your travels.

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

The chart illustrates April 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, April typically has an average temperature of 7°C (45°F), with highs reaching up to 26°C (80°F) and lows dropping to around -10°C (15°F).

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

April Precipitation in Ontario

In Ontario in April, the precipitation amount is 91 mm (3.6 in) over a period of 12 days.

April Precipitation Trends in Ontario

The chart displays monthly precipitation patterns in Ontario, with values for each month alongside April’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April’s conditions compare to those of other months. In Ontario, April typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 12 days.

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

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Millimeters (mm) Inches (in)

April Humidity in Ontario

In Ontario in April, humidity is 83%. With an average temperature of 7°C (45°F), this humidity feels like a chilly blanket wrapping around you, making travel somewhat uncomfortable as you navigate the dampness that settles in your clothes, leading to a heavy and muggy experience outdoors.

April Average Humidity in Ontario

This chart illustrates the average monthly humidity levels in Ontario, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, average humidity in Ontario is approximately 83%, offering insight into how humid the weather typically is during this month.

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

April UV Index in Ontario

In Ontario in April, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Ontario.

Maximum UV Index Levels in Ontario for April

The chart shows the monthly maximum UV Index (UVI) for Ontario in April, 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 April, the maximum UV index in Ontario typically reaches 8, which falls under the very high exposure category.

Data source: Ontario April 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 April 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 April’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 April’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