Ottawa Weather in August
August Climate Overview
August is Ottawa's second hottest month, similar to July but slightly cooler. Beach and lake swimming remain excellent, and long summer evenings are ideal for outdoor dining. Ottawa River water temperatures peak at 22-25 °C.
Source: Environment Canada Climate Normals 1991–2020 (Ottawa City station)
What to Expect
- Second hottest month; slightly cooler than July
- Days noticeably shorter — losing ~1.5 hrs daylight vs. peak
- Ottawa River water temperatures peak at 22-25 °C
- Long summer evenings ideal for patios and outdoor events
Things to Do in August
- Swimming at all city beaches (open until late August/Labour Day)
- Ottawa Fringe Festival (typically early August)
- Ottawa Greek Festival, Italian Week, and cultural festivals
- Gatineau Park lake swimming (Meech Lake, Philippe Lake)
- Camping in Gatineau Park
- ByWard Market at its busiest with outdoor produce and dining
What to Wear
Weather Tips for Visitors
- !Best swimming conditions of the year — water temperatures peak
- !Nights cool noticeably by late August — pack a light layer
- !Check ncc-ccn.gc.ca for beach water quality advisories
Seasonal Highlights
- Ottawa's summer festivals reach their peak
- Great time for day trips: Gatineau Park, Rideau Lakes
- Labour Day weekend: last major summer long weekend
August in Ottawa — FAQ
What is the weather like in Ottawa in August?
August in Ottawa has an average high of 25.6°C and low of 14.6°C. August is Ottawa's second hottest month, similar to July but slightly cooler. Beach and lake swimming remain excellent, and long summer evenings are ideal for outdoor dining. Ottawa River water temperatures peak at 22-25 °C.
What should I wear in Ottawa in August?
For August in Ottawa (25.6°C avg high), pack: Light summer clothing, Sunscreen and bug repellent, Light cardigan or sweater for cool evenings (end of month), Rain jacket for summer storms. Best swimming conditions of the year — water temperatures peak
Is August a good time to visit Ottawa?
August is hot in Ottawa with 248 hours of sunshine. Top activities include: Swimming at all city beaches (open until late August/Labour Day); Ottawa Fringe Festival (typically early August); Ottawa Greek Festival, Italian Week, and cultural festivals.
Does it snow in Ottawa in August?
No, Ottawa does not typically receive snow in August. Monthly precipitation averages 87 mm, falling as rain.
What events happen in Ottawa in August?
Key events in August: Ottawa's summer festivals reach their peak. Great time for day trips: Gatineau Park, Rideau Lakes. Labour Day weekend: last major summer long weekend. Peak summer swimming & festivals.
