The Climate and Weather of Toronto, Ontario

Toronto has a semi-continental climate, with a warm, humid summer and a cold winter.

Toronto's climate is modified by its location on the shores of Lake Ontario. The water in the lake ensures Toronto is warmer in winter and cooler in summer than it would otherwise be. The Great Lakes location is also the source of Toronto's summer humidity, which many people find uncomfortable.

Although Toronto is one of Canada's warmer cities in winter, winters are still severe, with snow on the ground most days between mid-December and mid-March.

Many factories and industrial plants in both Canada and the USA are located on the Great Lakes and smog has become something of a problem in Southern Ontario. About half of the smog is wind-borne from the USA.

Toronto's smog is very much a summer phenomenon. In 2005 downtown Toronto had 48 days when the city issued a smog advisory, a record high. The following year there were 11 advisories. In 2010, there were about a dozen advisories.

Toronto enjoys a fairly sunny climate. Toronto summers usually have an abundance of warm or hot sunny days. Winters are rather less sunny than in the prairie cities of Calgary and Winnipeg.

Toronto's day to day weather can be changeable throughout the year.