May Weather in Alliston, Canada

Last updated: June 18, 2025

In May, the average temperature in Alliston, Canada rests at a mild 13°C (55°F). Expect a wide range, with minimums dipping to -3°C (27°F) and maximums soaring to 32°C (90°F). Prepare for a bit of rain, as 99 mm (3.9 in) of precipitation falls over approximately 13 days. With an average humidity of 74%, it's a refreshing time to explore!

May Temperature in Alliston

In May in Alliston, the average temperature is 13°C (55°F). The maximum can reach 32°C (90°F), and the minimum can be as low as -3°C (27°F). Travelers should be prepared for a wide range of temperatures, ensuring they pack accordingly for both warm days and chilly evenings.

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

The chart illustrates May temperature patterns in Alliston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Alliston, May typically has an average temperature of 13°C (55°F), with highs reaching up to 32°C (90°F) and lows dropping to around -3°C (27°F).

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

May Precipitation in Alliston

In Alliston in May, the precipitation amount is 99 mm (3.9 in) over the course of 13 days.

May Precipitation Trends in Alliston

The chart displays monthly precipitation patterns in Alliston, 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 Alliston, May typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 13 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

May Humidity in Alliston

In Alliston in May, humidity is 74%. With an average temperature of 13°C (55°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities somewhat uncomfortable and demanding frequent breaks in shaded areas.

May Average Humidity in Alliston

This chart illustrates the average monthly humidity levels in Alliston, 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 Alliston is approximately 74%, 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 Alliston

In Alliston 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 Alliston.

Maximum UV Index Levels in Alliston for May

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

Data source: Alliston 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 Alliston Compares to Other Months

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

This table compares monthly weather conditions in Alliston, 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)	59 mm (2.3 inches)	93%	low
February Weather	-5°C (23°F)	62 mm (2.5 inches)	94%	moderate
March Weather	-1°C (31°F)	58 mm (2.3 inches)	87%	moderate
April Weather	5°C (42°F)	102 mm (4.0 inches)	82%	very high
May Weather	13°C (55°F)	99 mm (3.9 inches)	74%	very high
June Weather	18°C (65°F)	94 mm (3.7 inches)	68%	very high
July Weather	21°C (71°F)	90 mm (3.5 inches)	67%	very high
August Weather	20°C (69°F)	96 mm (3.8 inches)	67%	very high
September Weather	16°C (61°F)	68 mm (2.7 inches)	74%	high
October Weather	10°C (50°F)	98 mm (3.9 inches)	83%	moderate
November Weather	2°C (36°F)	76 mm (3.0 inches)	89%	moderate
December Weather	-3°C (28°F)	69 mm (2.7 inches)	91%	low