TODAY OCT01
TEMPERATURE66
HUMIDITY56
PRESSURE29.93
WIND COND.340 18.4
  • 6744Fri50%
  • 6645Sat
  • 6752Sun40%
  • 6648Mon40%40%
  • 6852Tue
daynightWeather update from Washington/Dulles International Airport, DC at

Key findings

  • The highest monthly average temperature in Fairfax for July is 78 degrees
  • The lowest monthly average temperature in Fairfax for January is 34 degrees
  • The most monthly precipitation in Fairfax occurs in May with 5.6 inches
  • The air quality index in Fairfax is 5% better than the national average
  • The pollution index in Fairfax is 92% better than the national average

Compare Fairfax, VA Weather

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      Fairfax Average Temperature

      In the event that the weather data was unavailable for this city, estimates based upon nearby cities were used.
      MonthTemp. (min)Temp. (max)Temp. (avg)Precipitation
      January24°F46°F34°F2.7"
      February25°F48°F36°F2.1"
      March33°F58°F45°F3.2"
      April43°F71°F56°F3.7"
      May52°F78°F65°F5.6"
      June61°F86°F74°F4.5"
      July66°F90°F78°F4.2"
      August65°F88°F76°F2.8"
      September58°F82°F69°F3.5"
      October46°F71°F58°F5.4"
      November35°F59°F46°F2.6"
      December29°F50°F39°F3.8"

      Fairfax air quality index & pollution index

      In the event that the air quality/pollution data was unavailable for this city, estimates based upon nearby cities were used.
      IndexFairfaxVirginiaNational
      Air quality index475850
      Pollution index380,1241,533,7925,066,862

      Fairfax air quality information

      MeasurementTotal
      Days measured365
      Days with good air quality209
      Days with moderate air quality145
      Days w/ poor A.Q. for sensitive groups10
      Days with unhealthy air quality1

      Fairfax air quality information

      PollutantTotal
      Arsenic0.003%
      Benzene0.005%
      Carbon Tetrachloride0.001%
      Lead0.001%
      Mercury0.000%

      Average monthly Fairfax temperature with heat index

      Fairfax monthly precipitation with daily maximum

      Fairfax monthly snow depth with daily maximum

      Fairfax monthly wind speed information

      Nearby cities with good air quality

      City, StatePopulationAir Quality IndexNational Avg.
      Springfield, VA29,952476%
      Sugarland Run, VA12,805476%
      Wakefield town, VA810476%
      Woodbridge, VA4,436476%
      Bethesda, MD62,608476%
      Fairfax, VA23,620476%

      Cities with similar population

      City, StatePopulationAir Quality IndexNational Avg.
      Greenbelt, MD23,623476%
      Palm Springs, FL23,5923628%
      North Laurel, MD23,590468%
      Marshall, TX23,6513824%
      Mequon, WI23,6634412%
      Fairfax, VA23,620476%
      Source: The Fairfax, VA weather data displayed above is derived from the NOAA (National Oceanic and Atmospheric). Air quality and pollution data is derived from the EPA (United States Environmental Protection Agency). Air quality and pollution levels measured in a particular area may not be representative of the entire county.