May Weather in Lewiston, United States

Last updated: June 24, 2025

In May, the average temperature in Lewiston, United States hovers around 15°C (59°F). However, be prepared for some fluctuations: the temperature can drop to a minimum of -1°C (31°F) or soar to a maximum of 32°C (91°F). With an average precipitation of 62 mm (2.4 in) spread over 6 days, and a humidity level of 81%, it's advisable to pack for variable weather conditions!

May Temperature in Lewiston

In May in Lewiston, the average temperature is 15°C (59°F). The maximum can reach 32°C (91°F), and the minimum can be as low as -1°C (31°F). It's a great time to pack layers and prepare for both warm days and cool nights while exploring the area.

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

The chart illustrates May temperature patterns in Lewiston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lewiston, May typically has an average temperature of 15°C (59°F), with highs reaching up to 32°C (91°F) and lows dropping to around -1°C (31°F).

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

May Precipitation in Lewiston

In Lewiston in May, the precipitation amount is 62 mm (2.4 in), spread over the course of 6 days.

May Precipitation Trends in Lewiston

The chart displays monthly precipitation patterns in Lewiston, 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 Lewiston, May typically receives around 62 mm (2.4 inches) of precipitation spread over approximately 6 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 Lewiston

In Lewiston in May humidity is 81%. With an average temperature of 15°C (59°F), this humidity feels like a heavy blanket draped over you, making traveling quite uncomfortable as you constantly wipe away beads of sweat and feel the stickiness clinging to your clothes.

May Average Humidity in Lewiston

This chart illustrates the average monthly humidity levels in Lewiston, 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 Lewiston is approximately 81%, 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 Lewiston

In Lewiston in May, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Lewiston.

Maximum UV Index Levels in Lewiston for May

The chart shows the monthly maximum UV Index (UVI) for Lewiston 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 Lewiston typically reaches 11, which falls under the extreme exposure category.

Data source: Lewiston 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 Lewiston Compares to Other Months

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

This table compares monthly weather conditions in Lewiston, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (40°F)	163 mm (6.4 inches)	86%	moderate
February Weather	5°C (41°F)	156 mm (6.1 inches)	85%	moderate
March Weather	7°C (44°F)	137 mm (5.4 inches)	85%	high
April Weather	11°C (51°F)	82 mm (3.2 inches)	82%	very high
May Weather	15°C (59°F)	62 mm (2.4 inches)	81%	extreme
June Weather	20°C (69°F)	15 mm (0.6 inches)	79%	extreme
July Weather	25°C (77°F)	2 mm (0.1 inches)	70%	extreme
August Weather	24°C (76°F)	4 mm (0.1 inches)	60%	very high
September Weather	20°C (68°F)	12 mm (0.5 inches)	62%	very high
October Weather	13°C (56°F)	52 mm (2.0 inches)	72%	high
November Weather	8°C (46°F)	97 mm (3.8 inches)	87%	moderate
December Weather	4°C (39°F)	118 mm (4.6 inches)	86%	moderate