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April Weather in Ontario, United States

Last updated: June 24, 2025

In Ontario, United States, the average temperature in April hovers around 6°C (44°F), with a minimum dipping to -3°C (27°F) and peaking at 23°C (73°F). Expect a total precipitation of 124 mm (4.9 in) across about 15 days, alongside an average humidity level of 88%. Stay prepared for a cool and damp month!

April Temperature in Ontario

In April in Ontario, the average temperature is 6°C (44°F). Maximums can reach 23°C (73°F), while minimums can drop as low as -3°C (27°F). This diverse temperature range makes Ontario an ideal destination for travelers seeking both mild days and crisp nights.

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 6°C (44°F), with highs reaching up to 23°C (73°F) and lows dropping to around -3°C (27°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.

April Precipitation in Ontario

In Ontario in April, the total precipitation amount is 124 mm (4.9 in) over a period of 15 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 124 mm (4.9 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec9494851241108014910383164110113
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
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April Humidity in Ontario

In Ontario in April humidity is 88%. With an average temperature of 6°C (44°F), this humidity feels like a damp chill that seeps into your bones, making outdoor adventures less inviting and requiring warm, layered clothing to stay comfortable while exploring.

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 88%, 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 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.
JanFebMarAprMayJunJulAugSepOctNovDec24681010997532
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.
 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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