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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 is a comfortable 17°C (63°F). However, temperatures can vary widely, with a minimum as low as -1°C (30°F) and a peak of 33°C (92°F). Rainfall is moderate, with about 130 mm (5.1 in) expected over 15 days. Expect high humidity levels too, averaging around 81%, which adds a bit of stickiness to the warm days.

May Temperature in Saint Marys

In May in Saint Marys, the average temperature is 17°C (63°F). The maximum can reach 33°C (92°F) and the minimum can be as low as -1°C (30°F). Be sure to pack clothing suitable for both warm and cool conditions while exploring.

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 17°C (63°F), with highs reaching up to 33°C (92°F) and lows dropping to around -1°C (30°F).
JanFebMarAprMayJunJulAugSepOctNovDec293241516372767368574135
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 total precipitation amount is 130 mm (5.1 in) over the course of 15 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 130 mm (5.1 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec74931029813012510910973968569
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 81%. With an average temperature of 17°C (63°F), this humidity feels like a warm blanket enveloping you, making travel slightly oppressive and calling for frequent breaks in air-conditioned spaces to recharge and enjoy your journey comfortably.

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 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%87%88%81%82%81%78%78%82%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.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
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 Weather-2°C (30°F)74 mm (2.9 inches)88%moderate
February Weather0°C (32°F)93 mm (3.7 inches)87%moderate
March Weather5°C (42°F)102 mm (4.0 inches)87%high
April Weather10°C (51°F)98 mm (3.9 inches)87%very high
May Weather17°C (63°F)130 mm (5.1 inches)81%very high
June Weather22°C (72°F)125 mm (4.9 inches)82%very high
July Weather24°C (76°F)109 mm (4.3 inches)81%very high
August Weather23°C (73°F)109 mm (4.3 inches)78%very high
September Weather20°C (69°F)73 mm (2.9 inches)78%very high
October Weather14°C (57°F)96 mm (3.8 inches)82%high
November Weather5°C (42°F)85 mm (3.4 inches)89%moderate
December Weather2°C (35°F)69 mm (2.7 inches)86%low

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