Ontario weather in May 2025

Expect 18°C daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Ontario in May. Check more long-term weather averages for Ontario in May before you book your next holiday to Ontario in 2025/2026.

  • 18°C maximum daytime temperature in May in Ontario (Toronto)18
    18°C max day temperature
  • 7 hours of sunshine per day
  • 11 days with some rainfall in May in Ontario (Toronto)11
    11 days with some rainfall
  • 8°C minimum night-time temperature in May in Ontario (Toronto)8
    8°C min night temperature
  • 15 hours of daylight per day in May in Ontario (Toronto)15
    15 hours of daylight per day
  • No heat & humidity in May in Ontario (Toronto)0
    No heat & humidity
  • 69 mm monthly rainfall in May in Ontario (Toronto)69
    69 mm of monthly rainfall
  • UV (maximum) index 7 (High) in May in Ontario (Toronto)7
    7 (High) UV index
  • 7°C sea temperature in May in Ontario (Toronto)7
    7°C sea temperature

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The May weather guide for Ontario (Toronto) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Top Ontario destinations

Below are average maximum temperatures at popular countries, regions and places in Ontario in May. Select a holiday destination to see more weather parameters.

All Ontario destinations

Metric (°C / mm)  |  Imperial (°F / inches)

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More about Canada

How hot is it in Ontario in May?

Daytime temperatures usually reach 18°C in Toronto, Ontario in May, falling to 8°C at night.

How sunny is it in Ontario in May?

There are normally 7 hours of bright sunshine each day in Toronto, Ontario in May - that's 50% of daylight hours.

Is the sea cold around Ontario in May?

The average sea temperature around Toronto, Ontario in May is 7°C.

Does it rain in Ontario in May?

There are usually 11 days with some rain in Toronto, Ontario in May and the average monthly rainfall is 69mm.

Ontario May sunrise & sunset times

Browse the sunrise and sunset times for Ontario in May 2025. Select a month to view Ontario sunrise and sunset times for the next 12 months. The Ontario sunrise and sunset times shown below are for Toronto.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Thursday, 1st May 2025 05:09 19:21
Friday, 16th May 2025 04:51 19:38
Saturday, 31st May 2025 04:39 19:52

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