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August Weather in Fairfax, United States

Last updated: June 24, 2025

In Fairfax, United States, the average temperature in August is a warm 27°C (80°F). Temperatures can range from a comfortable 16°C (60°F) to a sizzling 38°C (100°F). Expect about 103 mm (4.1 in) of precipitation spread over 10 days, with an average humidity of 73%, creating a humid yet vibrant atmosphere.

August Temperature in Fairfax

In August in Fairfax, the average temperature is 27°C (80°F). Maximums can reach 38°C (100°F), while minimums can dip as low as 16°C (60°F). Be prepared for warm weather, and pack lighter clothing for daytime adventures while bringing a light jacket 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 27°C (80°F), with highs reaching up to 38°C (100°F) and lows dropping to around 16°C (60°F).
JanFebMarAprMayJunJulAugSepOctNovDec373952586979828075614942
Data source: Temperature data for Fairfax 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.

August Precipitation in Fairfax

In Fairfax in August, the precipitation amount is 103 mm (4.1 in) over a span of 10 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 103 mm (4.1 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec57449710416010281103881213435
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Fairfax

In Fairfax in August humidity is 73%. With an average temperature of 27°C (80°F), this humidity feels like a warm, enveloping blanket that can make traveling feel sticky and slightly uncomfortable, prompting frequent breaks in the shade and plenty of hydration.

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 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%76%71%74%83%83%81%73%67%72%82%85%
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 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 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 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
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.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)57 mm (2.3 inches)77%moderate
February Weather4°C (39°F)43 mm (1.7 inches)76%high
March Weather11°C (52°F)97 mm (3.8 inches)71%high
April Weather15°C (59°F)104 mm (4.1 inches)73%very high
May Weather20°C (69°F)160 mm (6.3 inches)83%very high
June Weather26°C (79°F)101 mm (4.0 inches)83%extreme
July Weather28°C (82°F)80 mm (3.2 inches)81%extreme
August Weather27°C (80°F)103 mm (4.1 inches)73%very high
September Weather24°C (76°F)88 mm (3.4 inches)67%very high
October Weather16°C (61°F)121 mm (4.8 inches)72%high
November Weather9°C (49°F)34 mm (1.3 inches)82%moderate
December Weather6°C (43°F)35 mm (1.4 inches)85%moderate

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