Herndon, VA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Herndon, a town in Fairfax County, Virginia.
Today
86°F
Partly Sunny
Partly sunny, with a high near 86. Northeast wind 3 to 7 mph.
7-day forecast for Herndon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 86°F | Partly Sunny | 3 to 7 mph NE | 3% |
| Tonight | 70°F | Slight Chance Showers And Thunderstorms | 2 to 7 mph E | 68% |
| Wednesday | 86°F | Showers And Thunderstorms Likely | 2 to 7 mph SE | 69% |
| Wednesday Night | 72°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 7 mph S | 56% |
| Thursday | 90°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 7 to 12 mph S | 19% |
| Thursday Night | 72°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 19% |
| Friday | 90°F | Mostly Sunny then Chance Showers And Thunderstorms | 3 to 7 mph SW | 43% |
| Friday Night | 71°F | Chance Showers And Thunderstorms | 2 to 6 mph SW | 48% |
| Saturday | 89°F | Partly Sunny then Chance Showers And Thunderstorms | 2 to 6 mph SW | 54% |
| Saturday Night | 70°F | Chance Showers And Thunderstorms | 1 to 6 mph SW | 54% |
| Sunday | 89°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 1 to 6 mph W | 20% |
| Sunday Night | 72°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 mph SW | 20% |
| Monday | 92°F | Mostly Sunny | 2 to 7 mph W | 11% |
| Monday Night | 72°F | Partly Cloudy | 6 mph W | 14% |
Forecast source: National Weather Service (api.weather.gov) for Herndon (38.970, -77.387). Updated through the day.
Growing snapshot for Herndon
Last spring frost
Apr 15
First fall frost
Oct 24
Growing season
194 days
Hardiness zone
7b
More local growing data for Herndon: nearby ZIP 20170 weather · frost dates · planting calendar · Virginia frost dates
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Climate data from the nearest NOAA station, Washington Dc Dulles Ap, Va (5.3 mi from Herndon). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.