May Weather in Saint John, United States

Last updated: June 24, 2025

In May, the average temperature in Saint John, United States hovers around 15°C (59°F), with a minimum of 2°C (36°F) and a maximum reaching 32°C (90°F). Expect around 45 mm (1.8 in) of precipitation over the course of 7 days, coupled with an average humidity of 77%. Be prepared for a blend of warm and cool days as you explore!

May Temperature in Saint John

In May in Saint John, the average temperature is 15°C (59°F). Maximum temperatures can reach 32°C (90°F), while minimums can drop as low as 2°C (36°F). Be prepared for a wide range of temperatures when traveling during this month.

May Weather in Saint John: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Saint John, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint John, May typically has an average temperature of 15°C (59°F), with highs reaching up to 32°C (90°F) and lows dropping to around 2°C (36°F).

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

May Precipitation in Saint John

In Saint John in May, the precipitation amount is 45 mm (1.8 in) spread over a duration of 7 days.

May Precipitation Trends in Saint John

The chart displays monthly precipitation patterns in Saint John, 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 Saint John, May typically receives around 45 mm (1.8 inches) of precipitation spread over approximately 7 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 Saint John

In Saint John in May, humidity is 77%. With an average temperature of 15°C (59°F), this humidity feels like a warm blanket enveloping you, making it essential to stay hydrated and choose light, breathable clothing for comfortable travel.

May Average Humidity in Saint John

This chart illustrates the average monthly humidity levels in Saint John, 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 Saint John is approximately 77%, 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 Saint John

In Saint John in May, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Saint John.

Maximum UV Index Levels in Saint John for May

The chart shows the monthly maximum UV Index (UVI) for Saint John 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 Saint John typically reaches 8, which falls under the very high exposure category.

Data source: Saint John 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 Saint John Compares to Other Months

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

This table compares monthly weather conditions in Saint John, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (35°F)	62 mm (2.5 inches)	85%	low
February Weather	1°C (34°F)	74 mm (2.9 inches)	86%	moderate
March Weather	6°C (42°F)	56 mm (2.2 inches)	86%	moderate
April Weather	10°C (50°F)	48 mm (1.9 inches)	82%	high
May Weather	15°C (59°F)	45 mm (1.8 inches)	77%	very high
June Weather	20°C (68°F)	20 mm (0.8 inches)	79%	very high
July Weather	24°C (76°F)	2 mm (0.1 inches)	77%	very high
August Weather	24°C (75°F)	10 mm (0.4 inches)	62%	very high
September Weather	18°C (64°F)	22 mm (0.9 inches)	60%	high
October Weather	10°C (50°F)	54 mm (2.1 inches)	80%	moderate
November Weather	5°C (41°F)	74 mm (2.9 inches)	87%	moderate
December Weather	1°C (34°F)	70 mm (2.8 inches)	86%	low