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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Canada Scene Weather Desk. Data from Environment and Climate Change Canada and other national met services via Open-Meteo.
Ottawa weather is defined by dramatic seasonal swings: hot, humid summers and cold, snowy winters. The best months for comfortable sightseeing are May, June, September, and October, when temperatures are mild and the city’s parks and canal are at their finest.
What is the weather like in Ottawa each season?
Winter (December to March) brings average highs around -6°C and frequent snowfall, with the Rideau Canal Skateway opening when the ice is thick enough. Spring is short and wet, with temperatures climbing from 5°C in March to 18°C by May. Summer (June to August) sees highs of 26–30°C, often with high humidity and afternoon thunderstorms. Autumn is crisp and colourful, with September highs near 21°C before dropping to 5°C by November.
What should I pack for a trip to Ottawa?
For winter visits, pack a heavy parka, insulated boots, thermal layers, a warm hat, and gloves. Spring and autumn require a waterproof jacket and layers for cool mornings. Summer calls for light clothing, sunscreen, and an umbrella for sudden rain. Regardless of season, comfortable walking shoes are essential for exploring Parliament Hill and the ByWard Market.
When is the best time for snowbirds to visit Ottawa?
Snowbirds typically avoid Ottawa in winter. The best window is late May to early October, when the weather is warm enough for outdoor patios and festivals like Canada Day and the Tulip Festival.
Does Ottawa get extreme weather?
Yes. Ottawa can experience heat waves with humidex values above 40°C in summer, and extreme cold warnings when wind chill drops below -35°C in winter. Thunderstorms and occasional tornado watches also occur.
How does Ottawa weather compare to Toronto weather?
Ottawa is colder and snowier than Toronto in winter, with about 45 cm more snow annually. Summers are similar in temperature, though Ottawa’s humidity is slightly lower. For Toronto details, see our Toronto Weather page.