Ottawa weather in May
May in Ottawa: nice, rainy, with clean air — an excellent time to visit.
#4 of 12 months in Ottawa · #432 of 897 destinations to visit in May · comfort 83/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Ottawa in May
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Ottawa climate normals — May
| Daytime high | 19°C / 66°F | 😎 nice |
|---|---|---|
| Nighttime low | 8°C / 46°F | |
| Rainfall | 92 mm / 3.6 in | 🌧 rainy |
| Rainy days | 11 days | |
| Humidity | 63% | 💧 humid |
| Dew point | 6°C / 43°F | |
| Sunshine | 10.6 h/day | |
| Daylight | 14.9 h | |
| Wind | 16 km/h / 10 mph | |
| Snowfall | 0.4 cm / 0.2 in | |
| Air quality (US AQI) | 42 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Ottawa in May — FAQ
- Is May a good time to visit Ottawa?
- May in Ottawa: nice, rainy, with clean air — an excellent time to visit. It ranks #4 of 12 months for Ottawa on SeasonMap's comfort score (83/100).
- What is the weather like in Ottawa in May?
- In May, Ottawa averages a daily high of 18.8°C and a low of 7.8°C, with about 92.2 mm of rain over roughly 11.2 rainy days.
- What is the air quality in Ottawa in May?
- Ottawa has a mean US Air Quality Index of about 42 in May.