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May Weather in Mercersburg, United States

Last updated: June 24, 2025

In Mercersburg, United States, the average temperature in May hovers around 18°C (64°F), with extremes ranging from a chilly 0°C (32°F) to a warm 32°C (90°F). Visitors can expect about 126 mm (5.0 in) of precipitation over 14 days, contributing to an average humidity of 78%. Be prepared for a mix of weather as you explore this vibrant destination!

May Temperature in Mercersburg

In May in Mercersburg, the average temperature is 18°C (64°F). Maximums can reach 32°C (90°F) and minimums can be as low as 0°C (32°F). This diverse temperature range makes Mercersburg an ideal destination for travelers who enjoy both warm and cool conditions.

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

The chart illustrates May temperature patterns in Mercersburg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mercersburg, May typically has an average temperature of 18°C (64°F), with highs reaching up to 32°C (90°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec333743546472787569594437
Data source: Temperature data for Mercersburg 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 Mercersburg

In Mercersburg in May, the precipitation amount is 126 mm (5.0 in) over a span of 14 days.

May Precipitation Trends in Mercersburg

The chart displays monthly precipitation patterns in Mercersburg, 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 Mercersburg, May typically receives around 126 mm (5.0 inches) of precipitation spread over approximately 14 days.
JanFebMarAprMayJunJulAugSepOctNovDec6396871071261051301071221107696
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Mercersburg

In Mercersburg in May, humidity is 78%. With an average temperature of 18°C (64°F), this humidity feels like a warm, thick blanket wrapping around you, making traveling feel a bit sticky and sluggish, yet the coolness of the air tempers the intensity, inviting you to explore at a leisurely pace.

May Average Humidity in Mercersburg

This chart illustrates the average monthly humidity levels in Mercersburg, 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 Mercersburg is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Mercersburg

In Mercersburg 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 Mercersburg.

Maximum UV Index Levels in Mercersburg for May

The chart shows the monthly maximum UV Index (UVI) for Mercersburg 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 Mercersburg typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098743
Data source: Mercersburg 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 Mercersburg Compares to Other Months

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

This table compares monthly weather conditions in Mercersburg, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)63 mm (2.5 inches)86%moderate
February Weather3°C (37°F)95 mm (3.8 inches)86%moderate
March Weather6°C (43°F)87 mm (3.4 inches)86%high
April Weather12°C (54°F)107 mm (4.2 inches)84%very high
May Weather18°C (64°F)126 mm (5.0 inches)78%very high
June Weather22°C (72°F)105 mm (4.1 inches)79%very high
July Weather25°C (78°F)130 mm (5.1 inches)70%very high
August Weather24°C (75°F)107 mm (4.2 inches)59%very high
September Weather21°C (69°F)122 mm (4.8 inches)68%very high
October Weather15°C (59°F)110 mm (4.3 inches)80%high
November Weather6°C (44°F)76 mm (3.0 inches)86%moderate
December Weather3°C (38°F)96 mm (3.8 inches)85%moderate

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