May Weather in St. Thomas, Canada

Last updated: June 18, 2025

In May, the average temperature in St. Thomas, Canada hovers around 13°C (55°F), with a minimum dipping to -1°C (31°F) and a maximum reaching up to 26°C (78°F). During this time, you can expect about 99 mm (3.9 in) of precipitation spread over 13 days, contributing to an average humidity of 82%. Prepare accordingly for a mix of conditions!

May Temperature in St. Thomas

In May in St. Thomas, the average temperature is 13°C (55°F), with maximums reaching 26°C (78°F) and minimums dropping as low as -1°C (31°F). This diverse range of temperatures makes it essential for travelers to pack layers to adapt to the varying weather conditions.

May Weather in St. Thomas: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in St. Thomas, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In St. Thomas, May typically has an average temperature of 13°C (55°F), with highs reaching up to 26°C (78°F) and lows dropping to around -1°C (31°F).

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

May Precipitation in St. Thomas

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

May Precipitation Trends in St. Thomas

The chart displays monthly precipitation patterns in St. Thomas, 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 St. Thomas, 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 St. Thomas

In St. Thomas in May, humidity is 82%. With an average temperature of 13°C (55°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities sticky and uncomfortable for traveling.

May Average Humidity in St. Thomas

This chart illustrates the average monthly humidity levels in St. Thomas, 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 St. Thomas 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 St. Thomas

In St. Thomas 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 St. Thomas.

Maximum UV Index Levels in St. Thomas for May

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

Data source: St. Thomas 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 St. Thomas Compares to Other Months

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

This table compares monthly weather conditions in St. Thomas, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-3°C (27°F)	76 mm (3.0 inches)	90%	moderate
February Weather	-3°C (27°F)	79 mm (3.1 inches)	90%	moderate
March Weather	1°C (34°F)	81 mm (3.2 inches)	87%	moderate
April Weather	6°C (43°F)	106 mm (4.2 inches)	87%	very high
May Weather	13°C (55°F)	99 mm (3.9 inches)	82%	very high
June Weather	19°C (66°F)	93 mm (3.7 inches)	81%	very high
July Weather	22°C (72°F)	91 mm (3.6 inches)	79%	very high
August Weather	22°C (71°F)	96 mm (3.8 inches)	80%	very high
September Weather	18°C (65°F)	82 mm (3.2 inches)	81%	very high
October Weather	12°C (55°F)	123 mm (4.9 inches)	84%	high
November Weather	5°C (41°F)	94 mm (3.7 inches)	88%	moderate
December Weather	1°C (34°F)	77 mm (3.0 inches)	87%	low