September Weather in Toronto, United States

Last updated: June 24, 2025

The average temperature in Toronto, United States during September is a pleasant 20°C (68°F). Expect minimums dipping to 5°C (41°F) and maximums soaring to 34°C (93°F). Prepare for 120 mm (4.7 in) of precipitation spread over 10 days, coupled with an average humidity of 77%. Stay comfortable and ready for varying weather conditions!

September Temperature in Toronto

In September in Toronto, the average temperature is 20°C (68°F). Maximums can reach 34°C (93°F) and minimums can be as low as 5°C (41°F). Travelers should be prepared for warm days and cool nights, making layering essentials for this time of year.

September Weather in Toronto: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Toronto, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Toronto, September typically has an average temperature of 20°C (68°F), with highs reaching up to 34°C (93°F) and lows dropping to around 5°C (41°F).

Data source: Temperature data for Toronto generated using information from the Copernicus Climate Change Service.

September Precipitation in Toronto

In Toronto in September, the precipitation amount is 120 mm (4.7 in) spread over a duration of 10 days.

September Precipitation Trends in Toronto

The chart displays monthly precipitation patterns in Toronto, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Toronto, September typically receives around 120 mm (4.7 inches) of precipitation spread over approximately 10 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Toronto

In Toronto in September, humidity is 77%. With an average temperature of 20°C (68°F), this humidity feels like a warm, sticky embrace, making it essential for travelers to stay hydrated and take breaks in shaded areas to avoid feeling sluggish in the heat.

September Average Humidity in Toronto

This chart illustrates the average monthly humidity levels in Toronto, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Toronto is approximately 77%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Toronto

In Toronto in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Toronto.

Maximum UV Index Levels in Toronto for September

The chart shows the monthly maximum UV Index (UVI) for Toronto in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Toronto typically reaches 8, which falls under the very high exposure category.

Data source: Toronto September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Toronto Compares to Other Months

Weather in Toronto varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Toronto, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Toronto, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (31°F)	90 mm (3.6 inches)	88%	moderate
February Weather	1°C (35°F)	115 mm (4.5 inches)	88%	moderate
March Weather	5°C (41°F)	103 mm (4.0 inches)	87%	high
April Weather	11°C (51°F)	130 mm (5.1 inches)	87%	very high
May Weather	17°C (62°F)	134 mm (5.3 inches)	81%	very high
June Weather	21°C (70°F)	131 mm (5.2 inches)	83%	very high
July Weather	24°C (75°F)	134 mm (5.3 inches)	82%	very high
August Weather	23°C (73°F)	89 mm (3.5 inches)	76%	very high
September Weather	20°C (68°F)	120 mm (4.7 inches)	77%	very high
October Weather	14°C (57°F)	120 mm (4.7 inches)	82%	high
November Weather	5°C (42°F)	92 mm (3.6 inches)	89%	moderate
December Weather	2°C (36°F)	99 mm (3.9 inches)	86%	low