May Weather in Harriston, Canada

Last updated: June 18, 2025

In Harriston, Canada, the average temperature in May hovers around 12°C (54°F). However, be prepared for a varied climate, with minimums reaching -4°C (25°F) and maximums soaring to 30°C (87°F). During this month, you can expect approximately 103 mm (4.1 in) of precipitation spread over about 12 days, and the air is generally quite humid, with an average humidity of 82%.

May Temperature in Harriston

In May in Harriston, the average temperature is 12°C (54°F). Maximums can reach 30°C (87°F), while minimums can dip as low as -4°C (25°F). Travelers should be prepared for a wide range of temperatures during this time.

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

The chart illustrates May 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, May typically has an average temperature of 12°C (54°F), with highs reaching up to 30°C (87°F) and lows dropping to around -4°C (25°F).

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

May Precipitation in Harriston

In Harriston in May, the total precipitation amount is 103 mm (4.1 in), occurring over the course of 12 days.

May Precipitation Trends in Harriston

The chart displays monthly precipitation patterns in Harriston, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Harriston, May typically receives around 103 mm (4.1 inches) of precipitation spread over approximately 12 days.

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

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Millimeters (mm) Inches (in)

May Humidity in Harriston

In Harriston in May humidity is 82%. With an average temperature of 12°C (54°F), this humidity feels like a heavy blanket wrapping around you, making every step feel sluggish and sweat-inducing, which can be quite uncomfortable for traveling.

May Average Humidity in Harriston

This chart illustrates the average monthly humidity levels in Harriston, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Harriston is approximately 82%, offering insight into how humid the weather typically is during this month.

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

May UV Index in Harriston

In Harriston in May, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Harriston.

Maximum UV Index Levels in Harriston for May

The chart shows the monthly maximum UV Index (UVI) for Harriston in May, 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 May, the maximum UV index in Harriston typically reaches 9, which falls under the very high exposure category.

Data source: Harriston May 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 May 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 May’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 May’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