Temperatures in May
It's pleasantly warm in May in Ontario with an average temperature of 20°C. Temperatures this month range from a low of 16°C to a high of 26°C. At night, you can expect temperatures between 6°C and 15°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Ontario in May. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of May
The month of May starts in Ontario with mild temperatures, averaging around 18°C during the day and nights close to 8°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Mid-May
By mid-May, the average daytime temperature rises to around 21°C, with nights close to 10°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
End of May
By the end of May, the average daytime temperature in Ontario will be around 24°C, with nights close to 14°C. A shower might show up, but overall the weather will be dry and sunny.
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Precipitation in May
In May, there is an average of 65 mm of precipitation, spread over 10 days. The wind speed is around 4 Bft, mostly coming from the South.
The average precipitation chance is 33% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in May for Ontario. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Ontario in May |
London | ||
|---|---|---|---|
 Average Temperature |
20°C | 18°C | |
 High Temp |
26°C | 21°C | |
| Low Temp |
16°C | 15°C | |
 Total Precipitation |
65 mm | 46 mm | |
| Rainy Days |
10 days | 8 days | |
April
UV index
The UV index is a maximum of 6 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is May a good time to visit Ontario?
Want nice weather? Then May is a great time to be in Ontario. You’ll have pleasant temperatures and not too much rain this month.
Temperature records for Ontario in May
With 33°C, Ontario hit the highest temperature in the last 10 years in May 2015. The lowest daytime temperature in this month was 4°C in 2020. The extreme night temperatures ranged from a low of -3°C to a high of 23°C.
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Daily Temperature in May in Ontario
This chart shows the average daily temperatures, both day and night, for each day in May in Ontario, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in May in Ontario
The chart below shows the average daily precipitation in May for Ontario, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for May, you can expect around 10 days of rain in Ontario.
Daily UV Index in May in Ontario
This chart shows the average daily UV index in May in Ontario, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in May in Ontario Over the Years
This chart shows the average temperature in May in Ontario, measured in degrees Celsius, over the past years.
Total Precipitation in May in Ontario Over the Years
This chart shows the average precipitation in May in Ontario, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in May for Ontario
Click on a specific day in May for detailed info on the typical weather on that day in Ontario. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in May in Ontario
Have you been to Ontario in May?
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Average Weather in Ontario by Month
Click on a month below to see detailed weather info for Ontario. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
