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May Weather in Harleysville, United States

Last updated: June 24, 2025

In May, the average temperature in Harleysville, United States is a comfortable 17°C (63°F). However, be prepared for a range of temperatures—minimums can drop to 1°C (33°F) while highs can soar to 34°C (93°F). This month also brings about 144 mm (5.7 in) of precipitation over 14 days, contributing to a relatively high average humidity of 75%. Whether you prefer cooler or warmer weather, pack accordingly!

May Temperature in Harleysville

In May in Harleysville, the average temperature is 17°C (63°F). The maximum can reach 34°C (93°F) and the minimum can be as low as 1°C (33°F). This wide range of temperatures makes Harleysville an ideal destination for travelers who enjoy both warm and cooler weather.

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

The chart illustrates May temperature patterns in Harleysville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Harleysville, May typically has an average temperature of 17°C (63°F), with highs reaching up to 34°C (93°F) and lows dropping to around 1°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec343742536372777569594538
Data source: Temperature data for Harleysville 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 Harleysville

In Harleysville in May, the precipitation amount is 144 mm (5.7 in) over the course of 14 days.

May Precipitation Trends in Harleysville

The chart displays monthly precipitation patterns in Harleysville, 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 Harleysville, May typically receives around 144 mm (5.7 inches) of precipitation spread over approximately 14 days.
JanFebMarAprMayJunJulAugSepOctNovDec6710610510414411114716310010286101
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Harleysville

In Harleysville in May, humidity is 75%. With an average temperature of 17°C (63°F), this humidity feels like a warm embrace, making outdoor activities a bit sticky and requiring frequent breaks to stay refreshed during your travels.

May Average Humidity in Harleysville

This chart illustrates the average monthly humidity levels in Harleysville, 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 Harleysville is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%85%85%83%75%74%65%62%66%79%87%85%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Harleysville

In Harleysville 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 Harleysville.

Maximum UV Index Levels in Harleysville for May

The chart shows the monthly maximum UV Index (UVI) for Harleysville 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 Harleysville typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: Harleysville 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 Harleysville Compares to Other Months

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

This table compares monthly weather conditions in Harleysville, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)67 mm (2.7 inches)87%moderate
February Weather3°C (37°F)106 mm (4.2 inches)85%moderate
March Weather6°C (43°F)105 mm (4.1 inches)85%high
April Weather12°C (53°F)104 mm (4.1 inches)83%very high
May Weather17°C (63°F)144 mm (5.7 inches)75%very high
June Weather22°C (72°F)111 mm (4.4 inches)73%very high
July Weather25°C (78°F)147 mm (5.8 inches)65%very high
August Weather24°C (75°F)163 mm (6.4 inches)62%very high
September Weather21°C (69°F)100 mm (4.0 inches)66%very high
October Weather15°C (60°F)102 mm (4.0 inches)79%high
November Weather7°C (45°F)86 mm (3.4 inches)87%moderate
December Weather3°C (38°F)101 mm (4.0 inches)85%low

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