Click on a day for an hourly weather forecast
The temperatures in Ottawa in May are quite cold with temperatures between 8°C and 18°C, warm clothes are a must.
You can expect rain for roughly half of the month of May in Ottawa. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Please note that Ottawa can expect a few days of snow in May.
Our weather forecast can give you a great sense of what weather to expect in Ottawa in May 2025.
If you’re planning to visit Ottawa in the near future, we highly recommend that you review the 14 day weather forecast for Ottawa before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -7° / -14° | 5 | 5 | 22 | 89 mm | Awful | Ottawa in January |
| February | -5° / -13° | 5 | 3 | 21 | 85 mm | Awful | Ottawa in February |
| March | 1° / -6° | 8 | 8 | 16 | 85 mm | Awful | Ottawa in March |
| April | 9° / 1° | 11 | 13 | 7 | 122 mm | Awful | Ottawa in April |
| May | 18° / 8° | 8 | 23 | 1 | 116 mm | Ok | Ottawa in May |
| June | 22° / 12° | 7 | 23 | 0 | 129 mm | Ok | Ottawa in June |
| July | 25° / 15° | 6 | 25 | 0 | 129 mm | Perfect | Ottawa in July |
| August | 25° / 15° | 7 | 24 | 0 | 137 mm | Good | Ottawa in August |
| September | 21° / 10° | 5 | 25 | 0 | 102 mm | Good | Ottawa in September |
| October | 13° / 5° | 9 | 21 | 1 | 134 mm | Bad | Ottawa in October |
| November | 5° / -2° | 7 | 14 | 8 | 80 mm | Awful | Ottawa in November |
| December | -2° / -8° | 7 | 6 | 18 | 101 mm | Awful | Ottawa in December |