Ottawa Weather in May
During May, Ottawa experiences pleasant daytime temperatures of 20°C (68°F) and cooler nights around 7°C (45°F). Expect quite a bit of rainfall. Around 93 mm (3.7 in) is typical.
Rainfall in Ottawa in May
Expect around 12 days of rain based on historical data, with 93 mm (3.7 in) average. When showers do arrive, they tend to be on the heavier side. Worth being prepared even if rain days are not that numerous.
Temperature in Ottawa in May
The perfect temperature in Ottawa in May makes it a solid month to visit, with 20°C (68°F) during the day and 7°C (45°F) at night. The difference between afternoon and evening temperatures is usually noticeable. At 7°C (45°F) overnight, it gets properly cold after dark. On the bright side, cold nights tend to make for excellent sleeping conditions.
Sunshine in Ottawa in May
With approximately 231 hours of sunshine, the days are filled with clear skies. It makes it a perfect month for being outside.If your ideal day consists of dry skies and pleasant temperatures, May, August and September typically offer the best circumstances for Ottawa.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Canada, check out our Ottawa's climate page.
Ottawa Temperature in May
Min Temperature
7°C (45°F)
Max Temperature
20°C (68°F)
Chance of Rain
41%
Precipitation
93 mm (3.7 in)
Rainy days
12 days
Humidity
49%
Sunshine
231 hours
Percentage Sunshine
50%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Ottawa typically rise from around 16°C (61°F) at the start of May to approximately 22°C (72°F) by the end. Nights are cool, with lows typically ranging from 5°C (41°F) to 11°C (52°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather for Ottawa in May
Browse day-by-day weather records for Ottawa spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Ottawa historical weather extremes in May
Based on weather observations in Ottawa between 1976 and 2026, these are the recorded extremes during May.
- The hottest May day on record in Ottawa reached 35°C (95°F) (May 26, 2010).
- The lowest overnight temperature recorded in May was -6°C (21°F) (May 4, 1983).
Best Places in Canada in May
Find out more about the weather in Canada and which places have the best travel conditions in this month. See all of Canada in May →
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What to Wear in Ottawa in May
For Ottawa in May, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. High rain levels are expected, so pack waterproof gear and an umbrella or poncho. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.What To Do in Ottawa in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Canada, check out our Ottawa's climate page.
Temperature Rainfall Sunshine Humidity
See the full Ottawa climate overview or explore weather in Canada.
