Average annual temperatures for Ontario (8°C/46°F) are slightly above the average for Canada (4°C/39°F).
Average annual rainfall for Ontario (891mm/35 inches) is significantly above the average for Canada (705mm/28 inches).
July is the hottest or warmest month in Ontario, with an average maximum temperate of 28°C/82°F.
January is the coolest or coldest month in Ontario, with an average minimum temperate of -9°C/16°F.
June is the wettest or most rainy month in Ontario, with an average rainfall of 95mm/4 inches.
March is the driest or least rainy month in Ontario, with an average rainfall of 52mm/2 inches.
Amherstburg is the hottest or warmest place in Ontario, with an average maximum temperate of 11°C/52°F.
Thunder Bay is the coldest place in Ontario, with an average maximum temperate of 3°C/37°F.
Fort Erie is the most rainy or wettest place in Ontario, with an average annual rainfall of 1,167mm/46 inches.
Greater Sudbury is the least rainy or driest place in Ontario, with an average annual rainfall of 184mm/7 inches.
| Place | Min Temp | Max Temp | Avg Temp | Rainfall |
|---|---|---|---|---|
| Ajax | 5 | 13 | 9 | 938 |
| Amherstburg | 6 | 16 | 11 | 1,047 |
| Barrie | 4 | 12 | 8 | 768 |
| Brampton | 4 | 14 | 9 | 894 |
| Burlington | 4 | 14 | 9 | 771 |
| Cambridge | 4 | 14 | 9 | 771 |
| Camlachie | 6 | 14 | 10 | 975 |
| Cornwall | 1 | 13 | 7 | 864 |
| Corunna | 5 | 15 | 10 | 1,062 |
| Fort Erie | 5 | 14 | 10 | 1,167 |
| Fort Frances | -3 | 10 | 3 | 720 |
| Greater Sudbury | 0 | 10 | 5 | 184 |
| Guelph | 3 | 12 | 7 | 1,104 |
| Hamilton | 4 | 14 | 9 | 771 |
| Kingston | 3 | 12 | 8 | 1,056 |
| Kitchener | 3 | 12 | 7 | 1,104 |
| Lambton Shores | 6 | 14 | 10 | 975 |
| London | 4 | 14 | 9 | 1,106 |
| Markham | 4 | 14 | 9 | 894 |
| Milton | 4 | 14 | 9 | 771 |
| Mississauga | 6 | 14 | 10 | 831 |
| Nepean | 2 | 12 | 7 | 969 |
| Niagara Falls | 5 | 14 | 10 | 1,167 |
| Niagara-on-the-Lake | 5 | 14 | 10 | 886 |
| Oakville | 4 | 14 | 9 | 771 |
| Oshawa | 5 | 13 | 9 | 938 |
| Ottawa | 2 | 12 | 7 | 969 |
| Petrolia | 6 | 14 | 10 | 975 |
| Port Colborne | 5 | 14 | 10 | 886 |
| Richmond Hill | 4 | 14 | 9 | 894 |
| Sarnia | 6 | 14 | 10 | 975 |
| Sault Ste. Marie | 1 | 11 | 6 | 1,060 |
| St. Catharines | 5 | 14 | 10 | 886 |
| Thorold | 5 | 14 | 10 | 886 |
| Thunder Bay | -3 | 9 | 3 | 682 |
| Toronto | 4 | 14 | 9 | 894 |
| Tottenham | 2 | 12 | 7 | 852 |
| Vaughan | 4 | 14 | 9 | 894 |
| Waterloo | 3 | 12 | 7 | 1,104 |
| Welland | 5 | 14 | 10 | 886 |
| Windsor | 6 | 16 | 11 | 1,047 |