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May Weather in Saint Marys, United States

Last updated: June 24, 2025

In Saint Marys, United States, the average temperature in May hovers around 18°C (65°F), providing a mild climate for visitors. However, temperatures can swing dramatically—ranging from a chilly -2°C (29°F) to a warm 32°C (90°F). Expect 150 mm (5.9 in) of precipitation over about 17 days, contributing to an average humidity of 82%. Enjoy the diverse weather, but don’t forget to pack accordingly!

May Temperature in Saint Marys

In May in Saint Marys, the average temperature is 18°C (65°F). Maximum temperatures can reach 32°C (90°F), while minimums can drop as low as -2°C (29°F). This diverse range of temperatures makes Saint Marys an ideal destination for travelers seeking both warm and cool experiences.

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

The chart illustrates May temperature patterns in Saint Marys, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint Marys, May typically has an average temperature of 18°C (65°F), with highs reaching up to 32°C (90°F) and lows dropping to around -2°C (29°F).
JanFebMarAprMayJunJulAugSepOctNovDec333845546471767469594438
Data source: Temperature data for Saint Marys generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Saint Marys

In Saint Marys in May, the precipitation amount is 150 mm (5.9 in) over a span of 17 days.

May Precipitation Trends in Saint Marys

The chart displays monthly precipitation patterns in Saint Marys, 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 Marys, May typically receives around 150 mm (5.9 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec9512711715115018013411011111788119
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Saint Marys

In Saint Marys in May, humidity is 82%. With an average temperature of 18°C (65°F), this humidity feels like a warm, sticky embrace that can quickly leave travelers feeling fatigued and in need of frequent breaks to stay refreshed and hydrated.

May Average Humidity in Saint Marys

This chart illustrates the average monthly humidity levels in Saint Marys, 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 Marys is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%88%87%82%84%82%73%74%81%89%86%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Saint Marys

In Saint Marys in May, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Saint Marys.

Maximum UV Index Levels in Saint Marys for May

The chart shows the monthly maximum UV Index (UVI) for Saint Marys 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 Marys typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098643
Data source: Saint Marys 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 Marys Compares to Other Months

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

This table compares monthly weather conditions in Saint Marys, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)95 mm (3.7 inches)88%moderate
February Weather3°C (38°F)127 mm (5.0 inches)88%moderate
March Weather7°C (45°F)117 mm (4.6 inches)88%high
April Weather12°C (54°F)151 mm (6.0 inches)86%very high
May Weather18°C (65°F)150 mm (5.9 inches)82%very high
June Weather22°C (72°F)180 mm (7.1 inches)84%very high
July Weather24°C (76°F)134 mm (5.3 inches)82%very high
August Weather23°C (74°F)110 mm (4.3 inches)73%very high
September Weather21°C (70°F)111 mm (4.4 inches)73%very high
October Weather15°C (59°F)117 mm (4.6 inches)81%high
November Weather7°C (44°F)88 mm (3.5 inches)89%moderate
December Weather4°C (39°F)119 mm (4.7 inches)86%moderate

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