Do you need to know, when is the best time to go to Ontario? Then you should take a look here, what weather you can expect there during the year.
Ontario is part of Canada. Canada is a huge country, so the climate here varies from temperate in south to subarctic and arctic in north. Winters are sometimes tough, especially in the interior, where the climate is continental. You can expect snow in some places for five months of the year. Southern coastal parts of Canada have a temperate climate, with mild and rainy winters and quite warm summers.
When speaking about the usual weather in this area, the information is relevant for example for these popular places: Acton, Addington Highlands, Ajax, Algonquin Provincial Park, Almonte, Arnprior, Aurora, Aylmer, Bancroft, Barrie, Battersea, Bayham, Belleville, Blind River, Bobcaygeon, Bracebridge, Brampton, Brantford, Brock, Brockton, Brockville, Bruce County, Buckhorn, Burlington, Calabogie, Caledon, Cambridge, Carleton Place, Carp, Central Ontario, Chatham Kent, Clarington, Clinton, Cobalt, Cobourg, Cochrane, Collingwood, Cornwall, Dryden, Durham, East Gwillimbury, Eastern Ontario, Elgin County, Elliot Lake, Elmira, Elora, Embrun, Espanola, Essex, Essex County, Fergus, Fort Erie, Fort Frances, French River, Gananoque, Georgetown, Glen Williams, Golden Horseshoe, Grand Bend, Gravenhurst, Greater Toronto Area, Grey County, Grimsby, Guelph, Haliburton Highlands, Halton, Hamilton, Hanover, Hawkesbury, Hearst, Huntsville, Huron Kinloss, Huron County, Ingersoll, Ipperwash Beach, Kanata, Kapuskasing, Kawarthas, Kenora, Killaloe, Killarney, Kincardine, Kingston, Kingsville, Kirkland Lake, Kitchener, Lake Superior Provincial Park, Leamington, Leeds and the 1000 Islands, Limoges, Lincoln, Lindsay and Fenelon Falls, Lion's Head, London, Longlac, Lucan, Magnetawan, Manitoulin Island, Marathon, Markham, Maynooth, Merrickville, Midland, Milton, Mississauga, Moosonee, Morrisburg, Muskoka, Napanee, Newcastle, Newmarket, Niagara on the Lake, Niagara Falls, Niagara Peninsula, Nipigon, Norfolk County, North Algona Wilberforce, North Bay, Northern Ontario, Oakville, Orangeville, Orillia, Oshawa, Ottawa, Ottawa Rideau, Ottawa Valley, Owen Sound, Oxford County, Parry Sound, Peel, Pelee Island, Pembroke, Penetang, Perth, Petawawa, Peterborough, Pickering, Point Pelee National Park, Port Colborne, Port Dover, Port Hope, Port Stanley, Powassan, Prescott Russell, Prescott, Prince Edward County, Quetico Provincial Park, Quinte Northumberland, Red Rock, Region of Waterloo, Renfrew, Richmond Hill, Rockwood Conservation Area, Russell, Sarnia, Sault Sainte Marie, Scugog, Seaway Region, Simcoe County, Sioux Lookout, Smiths Falls, Southwestern Ontario, St. Catharines, St. Jacobs, St. Joseph Island, St. Marys, St. Thomas, Stratford, Sudbury, Temagami, Temiskaming Shores, Terrace Bay, Thunder Bay, Tillsonburg, Timmins, Tobermory, Toronto, Trenton, Tweed, Uxbridge, Vaughan, Verona, Village at Blue Mountain, Wasaga Beach, Waterloo, Waubaushene, Wawa, Welland, Wellington County, Westport, Whitby, White River, Wilno, Windsor, Woodstock, York, Zurich.
Let's look now what weather you can expect in the area around Toronto and in many other cities. The warmest month here is July, the average maximum temperature is 27.2 ℃ (80.96 ℉). The average minimum temperature in this month is 17.7 ℃ (63.86 ℉). The coldest month here is January, the average maximum temperature is -0.9 ℃ (30.38 ℉). The average minimum temperature in this month is -7.2 ℃ (19.04 ℉). The most rainy month here is January, the average number of rainy days is 15.3. The least rainy month here is July, the average number of rainy days is 10.3. 
When travelling around Ontario, always consider the altitude of the the place as well. We should remind you, that the highest point in Canada is Mount Logan (5959 m) and the lowest point is Atlantic Ocean (0 m). So there are huge differences in altitudes in this country and the weather is very different in them therefore. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Ontario in January is this: The average highest temperature in Ontario in January is -0.9 ℃ (30.38 ℉). The average lowest temperature is -7.2 ℃ (19.04 ℉). At the beginning of January you can expect higher temperatures, the average highest temperature is around 0.55 ℃ (32.99 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around -0.45 ℃ (31.19 ℉). The average number of rainy days in January is 15.3. The average rainfall is 62.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 8:58 (hours and minutes), in the middle of the month 9:17 and at the end of the month 9:49.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in February is this: The average highest temperature in Ontario in February is 0 ℃ (32 ℉). The average lowest temperature is -6 ℃ (21.2 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around -0.45 ℃ (31.19 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 2.35 ℃ (36.23 ℉). The average number of rainy days in February is 11.5. The average rainfall is 50.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 9:49 (hours and minutes), in the middle of the month 10:28 and at the end of the month 11:11.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.
Typical (usual) weather in Ontario in March is this: The average highest temperature in Ontario in March is 4.7 ℃ (40.46 ℉). The average lowest temperature is -1.8 ℃ (28.76 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 2.35 ℃ (36.23 ℉). At the end of March you can expect higher temperatures, the average highest temperature is around 8.2 ℃ (46.76 ℉). The average number of rainy days in March is 12.7. The average rainfall is 67.8 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:11 (hours and minutes), in the middle of the month 11:56 and at the end of the month 12:41.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in April is this: The average highest temperature in Ontario in April is 11.7 ℃ (53.06 ℉). The average lowest temperature is 4 ℃ (39.2 ℉). At the beginning of April you can expect lower temperatures, the average highest temperature is around 8.2 ℃ (46.76 ℉). At the end of April you can expect higher temperatures, the average highest temperature is around 15.2 ℃ (59.36 ℉). The average number of rainy days in April is 11.8. The average rainfall is 69.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:41 (hours and minutes), in the middle of the month 13:25 and at the end of the month 14:07.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.
Typical (usual) weather in Ontario in May is this: The average highest temperature in Ontario in May is 18.7 ℃ (65.66 ℉). The average lowest temperature is 9.9 ℃ (49.82 ℉). At the beginning of May you can expect lower temperatures, the average highest temperature is around 15.2 ℃ (59.36 ℉). At the end of May you can expect higher temperatures, the average highest temperature is around 21.35 ℃ (70.43 ℉). The average number of rainy days in May is 12.1. The average rainfall is 73.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 14:07 (hours and minutes), in the middle of the month 14:43 and at the end of the month 15:10.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.
Typical (usual) weather in Ontario in June is this: The average highest temperature in Ontario in June is 24 ℃ (75.2 ℉). The average lowest temperature is 15.3 ℃ (59.54 ℉). At the beginning of June you can expect lower temperatures, the average highest temperature is around 21.35 ℃ (70.43 ℉). At the end of June you can expect higher temperatures, the average highest temperature is around 25.6 ℃ (78.08 ℉). The average number of rainy days in June is 11.2. The average rainfall is 72.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 15:10 (hours and minutes), in the middle of the month 15:25 and at the end of the month 15:24.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in July is this: The average highest temperature in Ontario in July is 27.2 ℃ (80.96 ℉). The average lowest temperature is 17.7 ℃ (63.86 ℉). At the beginning of July you can expect lower temperatures, the average highest temperature is around 25.6 ℃ (78.08 ℉). At the end of July you can expect lower temperatures, the average highest temperature is around 26.1 ℃ (78.98 ℉). The average number of rainy days in July is 10.3. The average rainfall is 66.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 15:24 (hours and minutes), in the middle of the month 15:09 and at the end of the month 14:41.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in August is this: The average highest temperature in Ontario in August is 25 ℃ (77 ℉). The average lowest temperature is 17.2 ℃ (62.96 ℉). At the beginning of August you can expect higher temperatures, the average highest temperature is around 26.1 ℃ (78.98 ℉). At the end of August you can expect lower temperatures, the average highest temperature is around 22.95 ℃ (73.31 ℉). The average number of rainy days in August is 10.7. The average rainfall is 77.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 14:41 (hours and minutes), in the middle of the month 14:05 and at the end of the month 13:24.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in September is this: The average highest temperature in Ontario in September is 20.9 ℃ (69.62 ℉). The average lowest temperature is 13.6 ℃ (56.48 ℉). At the beginning of September you can expect higher temperatures, the average highest temperature is around 22.95 ℃ (73.31 ℉). At the end of September you can expect lower temperatures, the average highest temperature is around 17.35 ℃ (63.23 ℉). The average number of rainy days in September is 10.3. The average rainfall is 83.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 13:24 (hours and minutes), in the middle of the month 12:40 and at the end of the month 11:56.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in October is this: The average highest temperature in Ontario in October is 13.8 ℃ (56.84 ℉). The average lowest temperature is 7.5 ℃ (45.5 ℉). At the beginning of October you can expect higher temperatures, the average highest temperature is around 17.35 ℃ (63.23 ℉). At the end of October you can expect lower temperatures, the average highest temperature is around 10.8 ℃ (51.44 ℉). The average number of rainy days in October is 11.4. The average rainfall is 65 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:56 (hours and minutes), in the middle of the month 11:11 and at the end of the month 10:29.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in November is this: The average highest temperature in Ontario in November is 7.8 ℃ (46.04 ℉). The average lowest temperature is 2.4 ℃ (36.32 ℉). At the beginning of November you can expect higher temperatures, the average highest temperature is around 10.8 ℃ (51.44 ℉). At the end of November you can expect lower temperatures, the average highest temperature is around 4.9 ℃ (40.82 ℉). The average number of rainy days in November is 13. The average rainfall is 74.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 10:29 (hours and minutes), in the middle of the month 9:50 and at the end of the month 9:18.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Ontario in December is this: The average highest temperature in Ontario in December is 2 ℃ (35.6 ℉). The average lowest temperature is -3.5 ℃ (25.7 ℉). At the beginning of December you can expect higher temperatures, the average highest temperature is around 4.9 ℃ (40.82 ℉). At the end of December you can expect lower temperatures, the average highest temperature is around 0.55 ℃ (32.99 ℉). The average number of rainy days in December is 14.2. The average rainfall is 70.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 9:18 (hours and minutes), in the middle of the month 8:59 and at the end of the month 8:56.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.| Toronto | temperature: - | highest temperature: 2 ℃ (35.6 ℉) | lowest temperature: -3.5 ℃ (25.7 ℉) | rainfall: 70.5mm | rainy days: 14.2 |
| Ottawa | temperature: - | highest temperature: -2.8 ℃ (26.96 ℉) | lowest temperature: -10.8 ℃ (12.56 ℉) | rainfall: 82.3mm | rainy days: 17.7 |
| Thunder Bay | temperature: - | highest temperature: -5.9 ℃ (21.38 ℉) | lowest temperature: -17 ℃ (1.4 ℉) | rainfall: 38.4mm | rainy days: 12.2 |
| Sudbury | temperature: - | highest temperature: -4.9 ℃ (23.18 ℉) | lowest temperature: -13.9 ℃ (6.98 ℉) | rainfall: 68.3mm | rainy days: 17.9 |
| Windsor | temperature: - | highest temperature: 2.1 ℃ (35.78 ℉) | lowest temperature: -4.6 ℃ (23.72 ℉) | rainfall: 74.1mm | rainy days: 15 |