Mosquito season in Davison County, SD: when it starts and ends
Mosquito months in Davison County
In a normal year mosquito season in Davison County, SD starts around April 23 and ends around October 14, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Davison County, and when
- Start tipping out standing water weekly by April 9.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 14.
- 14 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check SD spray notices.
Davison County against the rest of SD
Davison County has the 8th longest season of 66 SD counties, at 174 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 47.4°F.
- Hutchinson County: April 22 to October 13 (174 days, 18 WNV)
- Turner County: April 22 to October 13 (174 days, 5 WNV)
- Bon Homme County: April 24 to October 13 (172 days, 14 WNV)
- Minnehaha County: April 24 to October 13 (172 days, 86 WNV)
West Nile in Davison County
From 1999 to 2025, CDC ArboNET counted 97 human West Nile cases in Davison County (23 neuroinvasive) across 17 years. The worst was 2005 with 30; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.