Ontario Weather by Month — Temperature & Rainfall Guide

Ontario is a region in Canada. Many people wonder what the weather conditions are in Ontario over the year. What is the best time to visit Ontario?

This page shows the average weather conditions by month in Ontario over the year in: January, February, March, April, May, June, July, August, September, October, November, December.

In January the weather in Ontario is generally less favorable. January is a winter month. The average maximum daytime temperatures are very low and range from -12°C (10°F) in Red Lake to 1°C (34°F) in Saint Catharines. On average, this month is one of the coldest months of the year in Ontario. So be prepared and make sure to dress up warm.

Find more detailed climate information for Ontario in January here.

In February the weather in Ontario is generally less favorable. February is a winter month. The average maximum daytime temperatures are very low and range from -9°C (16°F) in Red Lake to 2°C (36°F) in Chatham. It is a very cold month in some areas, so be prepared and make sure to dress up warm.

Find more detailed climate information for Ontario in February here.

In March the weather in Ontario is generally less favorable. The temperatures range from very low in Schreiber with -2°C (28°F) to low in Windsor with 7°C (45°F). It is a very cold month in some areas, so be prepared and make sure to dress up warm.

Find more detailed climate information for Ontario in March here.

In April the weather in Ontario ranges from less favorable in Toronto to mixed in Ottawa. The temperatures range from low in Schreiber with 4°C (39°F) to moderate in Windsor with 14°C (57°F).

Find more detailed climate information for Ontario in April here.

In May the weather in Ontario ranges from good in Toronto to excellent in Ottawa. The temperatures range from low in Schreiber with 9°C (48°F) to pleasant in Kemptville with 21°C (70°F).

Find more detailed climate information for Ontario in May here.

In June the weather in Ontario ranges from very good in Ottawa to excellent in Toronto. The temperatures range from moderate in Schreiber with 14°C (57°F) to high in Amherstburg with 26°C (79°F).

Find more detailed climate information for Ontario in June here.

In July the weather in Ontario ranges from very good in Ottawa to excellent in Toronto. July is a summer month. The temperatures range from pleasant in Schreiber with 18°C (64°F) to high in Amherstburg with 28°C (82°F). On average, this month is one of the warmest months of the year in Ontario. So be prepared and make sure to dress lightly.

Find more detailed climate information for Ontario in July here.

In August the weather in Ontario ranges from very good in Kingston to excellent in Toronto. August is a summer month. The temperatures range from pleasant in Niagara on the Lake with 20°C (68°F) to high in Amherstburg with 27°C (81°F).

Find more detailed climate information for Ontario in August here.

In September the weather in Ontario ranges from good in Niagara on the Lake to excellent in Toronto. September is a summer month. The temperatures range from moderate in Niagara on the Lake with 17°C (63°F) to high in Chatham with 24°C (75°F).

Find more detailed climate information for Ontario in September here.

In October the weather in Ontario ranges from mixed in Ottawa to good in Toronto. The temperatures range from low in Red Lake with 8°C (46°F) to moderate in Chatham with 16°C (61°F).

Find more detailed climate information for Ontario in October here.

In November the weather in Ontario is generally less favorable. The temperatures range from very low in Red Lake with -1°C (30°F) to low in Chatham with 10°C (50°F).

Find more detailed climate information for Ontario in November here.

In December the weather in Ontario is generally less favorable. December is a winter month. The temperatures range from very low in Red Lake with -9°C (16°F) to low in Saint Catharines with 4°C (39°F). It is a very cold month in some areas, so be prepared and make sure to dress up warm.

Find more detailed climate information for Ontario in December here.