Mosquito season in Grayson County, VA: when it starts and ends

Mosquito months in Grayson County

In a normal year mosquito season in Grayson County, VA starts around April 11 and ends around October 26, about 28 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Grayson County, and when

• Start tipping out standing water weekly by March 28.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 26.
• No West Nile cases since 2016, so bites in Grayson County are a nuisance; check window screens.

Grayson County against the rest of VA

Grayson County has the 116th longest season of 133 VA counties, at 198 days against 257 in Norfolk city and 172 in Highland County. Its mean temperature is 52°F.

• Norton city: April 11 to October 27 (199 days, 0 WNV)
• Giles County: April 11 to October 26 (198 days, 0 WNV)
• Montgomery County: April 11 to October 26 (198 days, 0 WNV)
• Roanoke County: April 11 to October 26 (198 days, 1 WNV)

West Nile in Grayson County

CDC ArboNET lists no human West Nile cases for Grayson County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 1 of those years.

Background: when mosquitoes go away for the winter; how the dates are worked out.