October Weather in Ontario, United States

Last updated: June 24, 2025

In October, the average temperature in Ontario, United States hovers around 12°C (55°F). Expect temperature swings, with a minimum reaching as low as -8°C (17°F) and a maximum soaring to 31°C (87°F). Be prepared for some light rain, as the area receives an average precipitation of 16 mm (0.6 in) over 2 days. With an average humidity of 65%, it’s a month of cool, refreshing weather!

October Temperature in Ontario

In October in Ontario, the average temperature is 12°C (55°F). The maximum can reach 31°C (87°F), while the minimum can be as low as -8°C (17°F). Travelers should be prepared for a wide range of temperatures, making it essential to pack both warm and cool weather clothing.

October Weather in Ontario: Daily Temperature Highs, Lows, and Averages

The chart illustrates October temperature patterns in Ontario, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ontario, October typically has an average temperature of 12°C (55°F), with highs reaching up to 31°C (87°F) and lows dropping to around -8°C (17°F).

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

October Precipitation in Ontario

In Ontario in October, the precipitation amount is 16 mm (0.6 in) over a period of 2 days.

October Precipitation Trends in Ontario

The chart displays monthly precipitation patterns in Ontario, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In Ontario, October typically receives around 16 mm (0.6 inches) of precipitation spread over approximately 2 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

October Humidity in Ontario

In Ontario in October, humidity is 65%. With an average temperature of 12°C (55°F), this humidity feels like a cool, damp embrace that can make exploring outdoors a refreshing yet slightly heavy experience, requiring travelers to dress in layers to stay comfortable while enjoying the sights.

October Average Humidity in Ontario

This chart illustrates the average monthly humidity levels in Ontario, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in Ontario is approximately 65%, offering insight into how humid the weather typically is during this month.

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

October UV Index in Ontario

In Ontario in October, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Ontario.

Maximum UV Index Levels in Ontario for October

The chart shows the monthly maximum UV Index (UVI) for Ontario in October, 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 October, the maximum UV index in Ontario typically reaches 5, which falls under the moderate exposure category.

Data source: Ontario October 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 October Weather in Ontario Compares to Other Months

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

This table compares monthly weather conditions in Ontario, showing how October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	0°C (33°F)	42 mm (1.7 inches)	88%	moderate
February Weather	2°C (36°F)	46 mm (1.8 inches)	89%	moderate
March Weather	8°C (47°F)	32 mm (1.3 inches)	85%	high
April Weather	12°C (55°F)	23 mm (0.9 inches)	79%	high
May Weather	17°C (64°F)	28 mm (1.1 inches)	71%	very high
June Weather	23°C (73°F)	16 mm (0.6 inches)	71%	extreme
July Weather	29°C (84°F)	1 mm (0.0 inches)	66%	very high
August Weather	27°C (82°F)	5 mm (0.2 inches)	50%	very high
September Weather	21°C (70°F)	10 mm (0.4 inches)	48%	very high
October Weather	12°C (55°F)	16 mm (0.6 inches)	65%	moderate
November Weather	6°C (43°F)	27 mm (1.1 inches)	84%	moderate
December Weather	1°C (35°F)	29 mm (1.1 inches)	87%	low