Click on a day for an hourly weather forecast
The temperatures in Ontario in May are comfortable with low of 14°C and and high up to 24°C.
There is little to no rain in Ontario during May, so it’s a lot easier to explore the city. Just remember to dress in warm layers, as it can still get pretty chilly.
Our weather forecast can give you a great sense of what weather to expect in Ontario in May 2025.
If you’re planning to visit Ontario in the near future, we highly recommend that you review the 14 day weather forecast for Ontario before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 19° / 9° | 2 | 29 | 0 | 57 mm | Good | Ontario in January |
| February | 19° / 9° | 2 | 26 | 0 | 63 mm | Good | Ontario in February |
| March | 20° / 10° | 2 | 29 | 0 | 36 mm | Good | Ontario in March |
| April | 22° / 12° | 1 | 29 | 0 | 22 mm | Good | Ontario in April |
| May | 24° / 14° | 0 | 31 | 0 | 7 mm | Perfect | Ontario in May |
| June | 28° / 18° | 0 | 30 | 0 | 1 mm | Perfect | Ontario in June |
| July | 31° / 21° | 0 | 31 | 0 | 10 mm | Good | Ontario in July |
| August | 32° / 22° | 0 | 31 | 0 | 6 mm | Good | Ontario in August |
| September | 31° / 21° | 0 | 30 | 0 | 5 mm | Good | Ontario in September |
| October | 26° / 17° | 1 | 30 | 0 | 10 mm | Perfect | Ontario in October |
| November | 22° / 12° | 1 | 29 | 0 | 22 mm | Good | Ontario in November |
| December | 18° / 9° | 3 | 28 | 0 | 72 mm | Good | Ontario in December |