May Weather in Fairfax, United States

Last updated: June 24, 2025

In May, the average temperature in Fairfax, United States is a pleasant 24°C (75°F). However, be prepared for a range of temperatures, with minimums dipping to 6°C (43°F) and maximums soaring up to 39°C (102°F). Expect about 94 mm (3.7 in) of precipitation spread over 9 days, contributing to an average humidity level of 75%.

May Temperature in Fairfax

In May in Fairfax, the average temperature is 24°C (75°F), with maximums that can reach 39°C (102°F) and minimums that can drop as low as 6°C (43°F). It's a great time for travelers to enjoy warm days while also being prepared for cooler evenings.

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 24°C (75°F), with highs reaching up to 39°C (102°F) and lows dropping to around 6°C (43°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 precipitation amount reaches 94 mm (3.7 in) over the course of 9 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 94 mm (3.7 inches) of precipitation spread over approximately 9 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 75%. With average temperature 24°C (75°F), this humidity feels like a thick blanket wrapping around you, making outdoor activities feel especially stifling and leaving you yearning for cool breezes and refreshingly cold drinks.

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 75%, 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 reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, 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 11, which falls under the extreme 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	10°C (50°F)	81 mm (3.2 inches)	86%	moderate
February Weather	13°C (56°F)	104 mm (4.1 inches)	81%	high
March Weather	16°C (60°F)	73 mm (2.9 inches)	81%	very high
April Weather	19°C (66°F)	119 mm (4.7 inches)	79%	very high
May Weather	24°C (75°F)	94 mm (3.7 inches)	75%	extreme
June Weather	26°C (79°F)	121 mm (4.8 inches)	75%	extreme
July Weather	28°C (82°F)	143 mm (5.6 inches)	80%	extreme
August Weather	27°C (81°F)	142 mm (5.6 inches)	81%	extreme
September Weather	26°C (78°F)	85 mm (3.3 inches)	83%	very high
October Weather	21°C (71°F)	72 mm (2.8 inches)	78%	very high
November Weather	14°C (57°F)	63 mm (2.5 inches)	85%	high
December Weather	11°C (53°F)	126 mm (5.0 inches)	87%	moderate