McNair, VA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for McNair, a community in Fairfax County, Virginia.
This Afternoon
84°F
Mostly Sunny
Mostly sunny, with a high near 84. North wind around 10 mph.
7-day forecast for McNair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 84°F | Mostly Sunny | 10 mph N | 10% |
| Tonight | 61°F | Mostly Cloudy | 9 mph N | 10% |
| Saturday | 79°F | Partly Sunny | 8 mph E | 10% |
| Saturday Night | 67°F | Mostly Cloudy | 8 mph SE | 10% |
| Sunday | 83°F | Partly Sunny then Chance Showers And Thunderstorms | 7 to 13 mph S | 50% |
| Sunday Night | 65°F | Showers And Thunderstorms Likely | 3 to 9 mph NW | 64% |
| Monday | 74°F | Chance Rain Showers | 7 to 12 mph NE | 40% |
| Monday Night | 62°F | Rain Showers Likely | 6 to 10 mph NE | 57% |
| Tuesday | 66°F | Rain Showers Likely | 12 mph NE | 61% |
| Tuesday Night | 56°F | Rain Showers Likely | 12 mph NE | 61% |
| Wednesday | 62°F | Rain Showers Likely | 12 mph NE | 55% |
| Wednesday Night | 56°F | Chance Showers And Thunderstorms | 10 mph NE | 51% |
| Thursday | 64°F | Chance Showers And Thunderstorms | 10 mph N | 51% |
| Thursday Night | 55°F | Chance Showers And Thunderstorms | 5 to 8 mph N | 35% |
Forecast source: National Weather Service (api.weather.gov) for McNair (38.952, -77.414). Updated through the day.
Growing snapshot for McNair
Last spring frost
Apr 15
First fall frost
Oct 24
Growing season
194 days
Hardiness zone
7b
More local growing data for McNair: nearby ZIP 20171 weather · frost dates · planting calendar · Virginia frost dates
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Fair Lakes
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Climate data from the nearest NOAA station, Washington Dc Dulles Ap, Va (3.7 mi from McNair). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.