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May Weather in Groton, United States

Last updated: June 24, 2025

In May, the average temperature in Groton, United States hovers around 14°C (57°F). However, be prepared for the extremes; temperatures can dip as low as -3°C (27°F) and soar to a maximum of 31°C (88°F). With an average precipitation amount of 137 mm (5.4 in) spread over 17 days, and an average humidity of 82%, it's wise to pack your umbrella and dress in layers for the varied weather!

May Temperature in Groton

In May in Groton, the average temperature is 14°C (57°F), with maximums reaching 31°C (88°F) and minimums dropping as low as -3°C (27°F). It's advisable to pack for a range of weather conditions to fully enjoy your travels.

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

The chart illustrates May temperature patterns in Groton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Groton, May typically has an average temperature of 14°C (57°F), with highs reaching up to 31°C (88°F) and lows dropping to around -3°C (27°F).
JanFebMarAprMayJunJulAugSepOctNovDec242733455766716962523730
Data source: Temperature data for Groton 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 Groton

In Groton in May, the total precipitation amount is 137 mm (5.4 in), occurring over a span of 17 days.

May Precipitation Trends in Groton

The chart displays monthly precipitation patterns in Groton, 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 Groton, May typically receives around 137 mm (5.4 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec89969112413710516311699155102103
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

May Humidity in Groton

In Groton in May, humidity is 82%. With an average temperature of 14°C (57°F), this humidity feels like a thick blanket enveloping you, making outdoor activities uncomfortable and travel more challenging due to the heavy, damp air.

May Average Humidity in Groton

This chart illustrates the average monthly humidity levels in Groton, 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 Groton is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%90%87%88%82%79%78%76%78%84%89%86%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Groton

In Groton 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 Groton.

Maximum UV Index Levels in Groton for May

The chart shows the monthly maximum UV Index (UVI) for Groton 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 Groton typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec346810101098642
Data source: Groton 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 Groton Compares to Other Months

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

This table compares monthly weather conditions in Groton, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)88 mm (3.5 inches)90%moderate
February Weather-3°C (27°F)96 mm (3.8 inches)90%moderate
March Weather1°C (34°F)91 mm (3.6 inches)87%high
April Weather7°C (45°F)124 mm (4.9 inches)88%very high
May Weather14°C (57°F)137 mm (5.4 inches)82%very high
June Weather19°C (66°F)105 mm (4.1 inches)79%very high
July Weather21°C (71°F)163 mm (6.4 inches)78%very high
August Weather20°C (69°F)116 mm (4.6 inches)76%very high
September Weather17°C (62°F)99 mm (3.9 inches)78%very high
October Weather11°C (52°F)155 mm (6.1 inches)84%high
November Weather3°C (37°F)102 mm (4.0 inches)89%moderate
December Weather-1°C (30°F)102 mm (4.0 inches)86%low

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