Canada September can still feel warm in parts of Canada, but the differences between regions are substantial. Osoyoos in British Columbia is the warmest and driest destination in this comparison, averaging 24°C (75°F) during the day with only 16 mm (0.6 in) of rain. Toronto offers the strongest big-city balance at 22°C (72°F) with 83 mm (3.3 in), while Montreal is equally warm but wetter. Vancouver is milder at 19°C (66°F) and receives 125 mm (4.9 in), despite relatively strong sunshine. Quebec City is cooler still at 20°C (68°F) with 121 mm (4.8 in) of rain. If dry, warm weather matters most, the southern Okanagan stands out. For a major city break, Toronto has the most favorable combination.
Canada in September weather at a glance
September is a transition month across Canada. Summer warmth can linger in southern Ontario and British Columbia's interior, while nights become cooler and rainfall increases in several coastal and eastern regions.
| Destination | Daytime | Nighttime | Rainfall | Rainy days | Sunshine |
|---|---|---|---|---|---|
| Osoyoos | 24°C (75°F) | 9°C (48°F) | 16 mm (0.6 in) | 7 | - |
| Toronto | 22°C (72°F) | 15°C (59°F) | 83 mm (3.3 in) | 10 | 195 hrs |
| Montreal | 22°C (72°F) | 11°C (52°F) | 102 mm (4 in) | 11 | 183 hrs |
| Vancouver | 19°C (66°F) | 12°C (54°F) | 125 mm (4.9 in) | 10 | 212 hrs |
| Quebec City | 20°C (68°F) | 9°C (48°F) | 121 mm (4.8 in) | 14 | 163 hrs |
Historical averages from Weather & Climate. Conditions in individual years will vary.
Osoyoos is the warmest and driest choice
Osoyoos in the southern Okanagan stands out with 24°C (75°F) daytime temperatures, 9°C (48°F) nights and only 16 mm (0.6 in) of rainfall in September. Rain is recorded on around seven days.
The dry interior climate is very different from coastal British Columbia. Vancouver receives almost eight times as much monthly rain, despite being only a few hundred kilometers away.
Warm afternoons combined with cool nights make September particularly pleasant for vineyard visits, lakeside time and driving through the Okanagan. The 15°C (59°F) difference between day and night is worth packing for.
Toronto has the best big-city balance
Toronto averages 22°C (72°F) during the day and 15°C (59°F) at night, with 83 mm (3.3 in) of rain over around ten days and 195 sunshine hours.
Compared with Montreal, the daytime temperature is identical, but Toronto is four degrees warmer at night and receives 19 mm (0.7 in) less rain. Compared with Vancouver, Toronto is three degrees warmer by day and substantially drier.
For a city trip where you still want mild evenings and a reasonable chance of dry days, Toronto is the strongest of Canada's four major cities compared here.
Montreal stays warm but turns cooler at night
Montreal also averages 22°C (72°F) during the day, but nights fall to 11°C (52°F). Monthly rainfall reaches 102 mm (4 in) over around 11 days, with approximately 183 hours of sunshine.
That cooler nighttime average is one of the first signs that autumn is arriving. Afternoons can still feel summery, while mornings and evenings call for an extra layer.
Weather is generally well suited to walking the city, but Toronto has the drier and milder nights if climate is the deciding factor.
Vancouver is mild, relatively sunny and wetter
Vancouver in September averages 19°C (66°F) during the day and 12°C (54°F) at night. Rainfall totals 125 mm (4.9 in) over around ten days, while sunshine reaches approximately 212 hours.
Interestingly, Vancouver has more sunshine hours than Toronto, Montreal or Quebec City in this comparison, even though its rainfall total is the highest. A wet monthly total does not necessarily mean a continuously grey month.
If your plans include city neighborhoods, seawall walks and nearby mountain scenery, September can be attractive. If low rainfall is your main concern, the interior of British Columbia is a much stronger choice.
Quebec City is cooler and wetter
Quebec City in September averages 20°C (68°F) during the day and 9°C (48°F) at night. Rainfall reaches 121 mm (4.8 in) over around 14 days, while sunshine totals about 163 hours.
It is the coolest of the four major cities in the table after dark and has the highest number of rainy days. The trade-off is atmosphere: September can begin to bring early autumn color to the region.
Where is driest in Canada in September?
Weather & Climate's September data identifies Osoyoos as one of the warmest and driest places in Canada, with 24°C (75°F) daytime temperatures and only 16 mm (0.6 in) of rain.
Among the major cities compared here, Toronto is driest at 83 mm (3.3 in), followed by Montreal at 102 mm (4 in), Quebec City at 121 mm (4.8 in) and Vancouver at 125 mm (4.9 in).
Which Canadian destination should you choose?
- For the warmest and driest weather: Osoyoos, with 24°C (75°F) days and only 16 mm (0.6 in) of rain.
- For the best big-city balance: Toronto, with 22°C (72°F) days and 83 mm (3.3 in) of rain.
- For Montreal: expect equally warm 22°C (72°F) afternoons but cooler nights and more rain.
- For Vancouver: expect mild 19°C (66°F) days, 212 sunshine hours and 125 mm (4.9 in) of rain.
- For early autumn atmosphere: Quebec City, with 20°C (68°F) days and cool 9°C (48°F) nights.
Where is the best weather in Canada in September?
Osoyoos is the clear winner if warmth and low rainfall matter most. Among major cities, Toronto has the strongest balance of mild temperatures and comparatively moderate rainfall.
Vancouver is sunnier than its rainfall total might suggest, while Montreal and Quebec City move more clearly toward autumn. September can be excellent across southern Canada, but choosing an interior or eastern location can make a large difference to both temperature and rain risk.