Best year time to visit Fairfax County

General weather information about Fairfax County

Average annual temperature is 14.3 °C

Absolute maximum temperature: 37.6 °C

Absolute minimum temperature: -9.6 °C

Number of sunny days: 178 days

Number of rainy days: 185 days

Number of snow days: 2 days

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* Weather data for Fairfax County United States is based on climate observations for 2026 year

Fairfax County air temperature forecast for each month

JanFebMarAprMayJunJulAugSepOctNovDec
Absolute maximum temperature (°C)18.223.426.532.029.333.037.633.736.627.525.416.4
Average daytime temperature (°C)9.812.213.322.222.827.431.730.426.521.013.410.2
Average temperature (°C)5.56.57.215.216.421.125.324.220.815.17.65.7
Average night temperature (°C)2.12.12.29.510.515.520.519.416.210.53.32.3
Absolute minimum temperature (°C)-3.3-9.6-5.31.34.311.117.715.29.95.3-5.8-3.7

Fairfax County monthly weather indicators

JanFebMarAprMayJunJulAugSepOctNovDec
Daylight maximum duration (h)10.011.012.013.014.014.014.014.013.011.010.09.0
Daylight mean duration (h)9.810.712.013.214.314.814.613.712.411.210.19.5
Daylight minimum duration (h)9.010.011.012.013.014.014.013.011.010.09.09.0
Sunshine mean duration (h)5.36.47.69.110.510.812.110.98.88.77.75.6
Precipitation (mm)6567641104897133541182956170
Sunny days13151418151371113192218
Rainy days17131712161724201712713
Snow days100000000010

Fairfax County - weather forecast by months

Fairfax County weather in januaryFairfax County weather in februaryFairfax County weather in marchFairfax County weather in aprilFairfax County weather in mayFairfax County weather in juneFairfax County weather in julyFairfax County weather in augustFairfax County weather in septemberFairfax County weather in octoberFairfax County weather in novemberFairfax County weather in december

Best time to visit Fairfax County:

The best time to visit Fairfax County during the most sunny months:

  • June — 10.8(h)
  • July — 12.1(h)
  • August — 10.9(h)

The largest precipitation sum in Fairfax County is at

  • April — 110(mm)
  • July — 133(mm)
  • September — 118(mm)
  • December — 170(mm)

    • Weather forecast in the closest to Fairfax County admin centers

    Weather forecast in the closest towns to Fairfax County

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    MapTrains schedule
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    Frequently asked questions

    When is the best time to visit Fairfax County?
    The historical weather data above shows the warmest, sunniest and driest months to help you choose the best time to visit Fairfax County.
    What is the weather like in Fairfax County?
    See average temperature, rainfall and daylight hours for Fairfax County by month in the table above.
    How many sunny days does Fairfax County have?
    The monthly weather statistics above show sunshine and rainfall patterns for Fairfax County throughout the year.