May Weather in Maine, United States

Last updated: June 24, 2025

In May, the average temperature in Maine, United States hovers around 13°C (56°F). Weather can be quite variable, with minimums dipping to -2°C (28°F) and maximums soaring to 33°C (92°F). Expect 103 mm (4.1 in) of precipitation spread over approximately 13 days, contributing to a relatively high average humidity of 77%.

May Temperature in Maine

In May in Maine, the average temperature is 13°C (56°F). Maximum temperatures can reach 33°C (92°F), while minimums can drop as low as -2°C (28°F). Be prepared for a wide range of temperatures during your visit.

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

The chart illustrates May temperature patterns in Maine, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Maine, May typically has an average temperature of 13°C (56°F), with highs reaching up to 33°C (92°F) and lows dropping to around -2°C (28°F).

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

May Precipitation in Maine

In Maine in May, the precipitation amount is 103 mm (4.1 in) spread over a duration of 13 days.

May Precipitation Trends in Maine

The chart displays monthly precipitation patterns in Maine, 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 Maine, May typically receives around 103 mm (4.1 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 Maine

In Maine in May humidity is 77%. With average temperature 13°C (56°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities sweaty and uncomfortable.

May Average Humidity in Maine

This chart illustrates the average monthly humidity levels in Maine, 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 Maine 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 Maine

In Maine 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 Maine.

Maximum UV Index Levels in Maine for May

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

Data source: Maine 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 Maine Compares to Other Months

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

This table compares monthly weather conditions in Maine, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (17°F)	34 mm (1.3 inches)	89%	low
February Weather	-8°C (17°F)	50 mm (2.0 inches)	90%	moderate
March Weather	-1°C (31°F)	53 mm (2.1 inches)	87%	moderate
April Weather	5°C (42°F)	98 mm (3.9 inches)	84%	high
May Weather	13°C (56°F)	103 mm (4.1 inches)	77%	very high
June Weather	19°C (67°F)	102 mm (4.0 inches)	75%	very high
July Weather	22°C (71°F)	117 mm (4.6 inches)	74%	very high
August Weather	19°C (67°F)	121 mm (4.8 inches)	73%	very high
September Weather	16°C (61°F)	83 mm (3.3 inches)	78%	high
October Weather	8°C (47°F)	109 mm (4.3 inches)	84%	moderate
November Weather	0°C (32°F)	50 mm (2.0 inches)	89%	moderate
December Weather	-5°C (23°F)	52 mm (2.1 inches)	87%	low