May Weather in Fairfax, United States

Last updated: June 24, 2025

In May, the average temperature in Fairfax, United States is a comfortable 15°C (60°F), with lows dropping to a chilly 0°C (32°F) and highs reaching a sizzling 36°C (96°F). Expect some rain, with 124 mm (4.9 in) of precipitation spread over 13 days. The air is quite humid, averaging around 78%, contributing to the vibrant atmosphere of the season.

May Temperature in Fairfax

In May in Fairfax, the average temperature is 15°C (60°F). Maximums can reach 36°C (96°F), while minimums can drop as low as 0°C (32°F). Be prepared for a wide range of temperatures and pack accordingly for your travels!

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

The chart illustrates May temperature patterns in Fairfax, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fairfax, May typically has an average temperature of 15°C (60°F), with highs reaching up to 36°C (96°F) and lows dropping to around 0°C (32°F).

Data source: Temperature data for Fairfax generated using information from the Copernicus Climate Change Service.

May Precipitation in Fairfax

In Fairfax in May, the total precipitation amount is 124 mm (4.9 in) over a span of 13 days.

May Precipitation Trends in Fairfax

The chart displays monthly precipitation patterns in Fairfax, 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 Fairfax, May typically receives around 124 mm (4.9 inches) of precipitation spread over approximately 13 days.

Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

May Humidity in Fairfax

In Fairfax in May, humidity is 78%. With an average temperature of 15°C (60°F), this humidity feels like a warm, damp embrace that can make outdoor activities a bit uncomfortable, highlighting the importance of staying hydrated and taking breaks in the shade while exploring.

May Average Humidity in Fairfax

This chart illustrates the average monthly humidity levels in Fairfax, 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 Fairfax is approximately 78%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Fairfax

In Fairfax in May, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Fairfax.

Maximum UV Index Levels in Fairfax for May

The chart shows the monthly maximum UV Index (UVI) for Fairfax 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 Fairfax typically reaches 9, which falls under the very high exposure category.

Data source: Fairfax 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 Fairfax Compares to Other Months

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

This table compares monthly weather conditions in Fairfax, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (16°F)	26 mm (1.0 inches)	87%	moderate
February Weather	-9°C (16°F)	27 mm (1.1 inches)	90%	moderate
March Weather	0°C (33°F)	62 mm (2.5 inches)	85%	moderate
April Weather	6°C (43°F)	80 mm (3.1 inches)	84%	very high
May Weather	15°C (60°F)	124 mm (4.9 inches)	78%	very high
June Weather	22°C (72°F)	106 mm (4.2 inches)	80%	very high
July Weather	23°C (74°F)	123 mm (4.8 inches)	81%	very high
August Weather	21°C (71°F)	124 mm (4.9 inches)	81%	very high
September Weather	18°C (65°F)	118 mm (4.6 inches)	81%	very high
October Weather	9°C (48°F)	97 mm (3.8 inches)	84%	moderate
November Weather	1°C (34°F)	30 mm (1.2 inches)	88%	moderate
December Weather	-4°C (24°F)	40 mm (1.6 inches)	84%	low