Fairfax County Climate
Fairfax County, Virginia
Avg Annual Temp
54.9°F
Annual Precip
43.4"
Annual Snowfall
19.8"
Extreme Heat Days
23.05
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Fairfax County Weather
Predictable Mid-Atlantic Weather
Fairfax County’s 54.9°F annual average temperature sits right near the national median. It experiences a classic four-season climate typical of the Mid-Atlantic region.
Cooler Than the State Average
The county is exactly one degree cooler than the Virginia state average of 55.9°F. This difference reflects the slightly harsher winters found in Northern Virginia.
Consistent Regional Precipitation
Fairfax receives 43.4 inches of annual precipitation, slightly less than the state average of 45.7 inches. Its 19.8 inches of annual snow is typical for the Northern Virginia corridor.
Balanced Seasonal Extremes
Residents face 23 days of extreme heat over 90°F each summer. Winters are cold but manageable, with an average December-February temperature of 35.5°F.
Ready for Every Season
You will need a full wardrobe ranging from heavy parkas for the 19.8 inches of snow to light clothing for the 23 heat days. A balanced HVAC system is vital for year-round comfort.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.