September Weather in Harriston, Canada

Last updated: June 18, 2025

In September, the average temperature in Harriston, Canada is a mild 15°C (60°F). However, temperatures can vary significantly, with a minimum of -1°C (30°F) and a maximum reaching up to 31°C (87°F). Expect 94 mm (3.7 in) of precipitation over 11 days, contributing to an average humidity of 81%.

September Temperature in Harriston

In September in Harriston, the average temperature is 15°C (60°F). Maximums can reach 31°C (87°F), while minimums can drop as low as -1°C (30°F). This makes Harriston a destination with a diverse climate, so travelers should be prepared for both warm and cool conditions.

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

The chart illustrates September temperature patterns in Harriston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Harriston, September typically has an average temperature of 15°C (60°F), with highs reaching up to 31°C (87°F) and lows dropping to around -1°C (30°F).

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

September Precipitation in Harriston

In Harriston in September, the precipitation amount is 94 mm (3.7 in) over the course of 11 days.

September Precipitation Trends in Harriston

The chart displays monthly precipitation patterns in Harriston, 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 Harriston, September typically receives around 94 mm (3.7 inches) of precipitation spread over approximately 11 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 Harriston

In Harriston in September, humidity is 81%. With an average temperature of 15°C (60°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities feel sluggish and draining, which can challenge even the best-prepared traveler.

September Average Humidity in Harriston

This chart illustrates the average monthly humidity levels in Harriston, 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 Harriston is approximately 81%, 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 Harriston

In Harriston in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Harriston.

Maximum UV Index Levels in Harriston for September

The chart shows the monthly maximum UV Index (UVI) for Harriston 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 Harriston typically reaches 7, which falls under the high exposure category.

Data source: Harriston 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 Harriston Compares to Other Months

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

This table compares monthly weather conditions in Harriston, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (21°F)	76 mm (3.0 inches)	90%	low
February Weather	-6°C (22°F)	83 mm (3.3 inches)	90%	moderate
March Weather	-1°C (30°F)	70 mm (2.8 inches)	87%	moderate
April Weather	5°C (41°F)	107 mm (4.2 inches)	87%	very high
May Weather	12°C (54°F)	103 mm (4.1 inches)	82%	very high
June Weather	18°C (64°F)	106 mm (4.2 inches)	81%	very high
July Weather	20°C (69°F)	89 mm (3.5 inches)	79%	very high
August Weather	19°C (67°F)	110 mm (4.3 inches)	80%	very high
September Weather	15°C (60°F)	94 mm (3.7 inches)	81%	high
October Weather	9°C (49°F)	111 mm (4.4 inches)	84%	moderate
November Weather	1°C (35°F)	95 mm (3.8 inches)	88%	moderate
December Weather	-3°C (28°F)	83 mm (3.2 inches)	87%	low