Mosquito season in Turner County, SD: when it starts and ends

Mosquito months in Turner County

In a normal year mosquito season in Turner County, SD starts around April 22 and ends around October 13, about 25 weeks.

What to do in Turner County, and when

Start tipping out standing water weekly by April 8.
Book any yard treatment for late April, ahead of the July peak.
Repellent can go away after October 13.
5 West Nile cases since 2016 (last 2022): you should use repellent at dusk July to August, more so if over 60.

Turner County against the rest of SD

Turner County has the 7th longest season of 66 SD counties, at 174 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 47.1°F.

Union County: April 22 to October 15 (176 days, 13 WNV)
Hutchinson County: April 22 to October 13 (174 days, 18 WNV)
Davison County: April 23 to October 14 (174 days, 14 WNV)
Bon Homme County: April 24 to October 13 (172 days, 14 WNV)

West Nile in Turner County

From 1999 to 2025, CDC ArboNET counted 44 human West Nile cases in Turner County (10 neuroinvasive) across 12 years. The worst was 2003 with 20; the latest was 2022.

See how the dates are worked out, and reading the West Nile counts.