Temperature in Ontario in September

Daytime highs, nighttime lows and the warmest cities in Ontario, Canada this September.

Ontario, Canada, a region in Canada, experiences maximum daytime temperatures in September ranging from 17°C (63°F) in Niagara on the Lake to 24°C (75°F) in Chatham. Nighttime temperatures generally drop to 14°C (57°F) in Chatham and 9°C (48°F) in Niagara on the Lake. During September, summer is in full swing.

What is the temperature of the different cities in Ontario, Canada in September?

Explore the map below to discover average September temperatures at the top destinations in Ontario. For a deeper dive, simply click on any destination dot.

Select a Month

Check the conditions for any month of the year.

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For a detailed overview over the year and the best time to visit Ontario, check out our Ontario's climate page.

See also: Ontario weather by month.

Best Places to Visit in Ontario in September

Click on a destination dot for more details. Toggle the map to compare temperatures or precipitation across Ontario.

Conditions Temperatures Precipitation
Avg daytime high -5°C (23°F) cold → 32°C (90°F) hot

Marker color shows the average daytime high temperature in September: blue is cold, red is hot.

See all September weather averages, cities and regions in Ontario

Ontario temperatures in September: frequently asked questions

How hot does it get in Ontario, Canada in September?

Expect daytime temperatures around 22°C (72°F) in Toronto. That makes September a high month for Ontario, Canada.

How cold does it get at night in Ontario, Canada in September?

Nighttime temperatures in Toronto typically drop to around 15°C (59°F) in September.

What is the warmest city in September in Ontario, Canada?

Chatham tops the warmest city list in our database with average maximum daytime temperatures around 24°C (75°F) and a minimum nighttime temperature of around 14°C (57°F).

What is the coldest city in September in Ontario, Canada?

When looking through our records, we find that Niagara on the Lake stands out as the coolest city in Ontario, Canada for the month of September. Daytime highs average 17°C (63°F) and it cools down to about 9°C (48°F) at night.

How much sun does Ontario, Canada get in September?

Across Ontario, Canada, sunshine in September ranges from moderately sunny in Kingston (165 hours) to sunny in Mississauga (216 hours).

Interested in more climate information?

We have much more information about the climate in Ontario.

Weather and climate has detailed information for every country in the world. Are you going to Canada? Get detailed historical weather averages for many cities in Canada.

Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.

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