Mosquito season in Chesterfield County, SC: when it starts and ends

Mosquito months in Chesterfield County

In a normal year mosquito season in Chesterfield County, SC starts around March 21 and ends around November 13, about 34 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 Chesterfield County, and when

• Start tipping out standing water weekly by March 7.
• Book any yard treatment for late March, ahead of the July peak.
• Repellent can go away after November 13.
• No West Nile cases since 2016, so bites in Chesterfield County are a nuisance; check window screens.

Chesterfield County against the rest of SC

Chesterfield County has the 42nd longest season of 46 SC counties, at 237 days against 349 in Charleston County and 209 in Cherokee County. Its mean temperature is 62.5°F.

• Chester County: March 20 to November 13 (238 days, 1 WNV)
• York County: March 21 to November 14 (238 days, 6 WNV)
• Spartanburg County: March 24 to November 11 (232 days, 4 WNV)
• Union County: March 24 to November 10 (231 days, 2 WNV)

West Nile in Chesterfield County

CDC ArboNET lists no human West Nile cases for Chesterfield County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 3 of those years.

See how the dates are worked out, and when mosquitoes go away for the winter.