August Weather in Fairfax, United States

Last updated: June 24, 2025

In August, the average temperature in Fairfax, United States is a comfortable 22°C (73°F). Expect a temperature range from a cool 10°C (51°F) to a warm 34°C (94°F). With an average precipitation of 77 mm (3.0 in) spread over 9 days, and a humidity level of 77%, be prepared for a mix of sunny and rainy days!

August Temperature in Fairfax

In August in Fairfax, the average temperature is 22°C (73°F), with maximums reaching up to 34°C (94°F) and minimums dropping as low as 10°C (51°F). This makes it a great time for travelers to enjoy comfortable daytime activities while also being prepared for cooler evenings.

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

The chart illustrates August 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, August typically has an average temperature of 22°C (73°F), with highs reaching up to 34°C (94°F) and lows dropping to around 10°C (51°F).

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

August Precipitation in Fairfax

In Fairfax in August, the precipitation amount is 77 mm (3.0 in) over the course of 9 days.

August Precipitation Trends in Fairfax

The chart displays monthly precipitation patterns in Fairfax, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Fairfax, August typically receives around 77 mm (3.0 inches) of precipitation spread over approximately 9 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

August Humidity in Fairfax

In Fairfax in August, humidity is 77%. With an average temperature of 22°C (73°F), this humidity feels like a warm, sticky embrace, making travel a bit uncomfortable but manageable as you explore the sights while seeking shade and refreshing drinks.

August Average Humidity in Fairfax

This chart illustrates the average monthly humidity levels in Fairfax, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Fairfax is approximately 77%, offering insight into how humid the weather typically is during this month.

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

August UV Index in Fairfax

In Fairfax in August, 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 August

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

Data source: Fairfax August 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 August 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 August’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 August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (21°F)	47 mm (1.9 inches)	81%	moderate
February Weather	-5°C (23°F)	56 mm (2.2 inches)	81%	moderate
March Weather	3°C (38°F)	73 mm (2.9 inches)	81%	high
April Weather	9°C (48°F)	81 mm (3.2 inches)	82%	very high
May Weather	16°C (62°F)	160 mm (6.3 inches)	78%	very high
June Weather	23°C (73°F)	134 mm (5.3 inches)	81%	extreme
July Weather	24°C (76°F)	85 mm (3.3 inches)	79%	very high
August Weather	22°C (73°F)	77 mm (3.0 inches)	77%	very high
September Weather	19°C (67°F)	127 mm (5.0 inches)	78%	very high
October Weather	11°C (53°F)	140 mm (5.5 inches)	78%	high
November Weather	3°C (38°F)	47 mm (1.9 inches)	87%	moderate
December Weather	-1°C (30°F)	44 mm (1.7 inches)	84%	moderate