Climate graphs for the various provinces and territories may be found in the relevant entries below.

Summer thunderstorms are common throughout Canada. Occasionally, these may become severe. Tornados also occur throughout Canada, with May to September being prime months. The peak season is June and early July in southern Ontario, Alberta, southeastern Québec, and a band stretching from southern Saskatchewan and Manitoba, through to Thunder Bay. The interior of British Columbia and western New Brunswick are also tornado zones. Earth tremors occur in the western mountains. Forest fires can occur at any time, regardless of the season, particularly in the grasslands and forests of western Canada.

March: Moderate temperatures. Winter clothing with some mediumweight clothing.
April: Milder days but the evenings are cool. Mediumweight clothing including a topcoat is recommended.
May: Warm days but cool at night. Mediumweight and summer clothing recommended.
June: Warm, summer clothing with some mediumweight clothing for cool evenings. The weather in June is ideal for travel and all outdoor activities.
July/August: These are the warmest months of the year. Lightweight summer clothing is recommended.
September: Warm days and cool evenings. Light- to mediumweight clothing recommended.
October: Cool, with the first frost in the air.
November: Cool to frosty. Medium- to heavyweight clothing is recommended. First signs of snow. Motorists should have cars prepared for winter and snow tyres are recommended.
December/January/February: Winter temperatures. Winter clothing is necessary (eg overcoat, hat, boots and gloves). Heavy snowfall in most provinces.