Mosquito season in Deuel County, SD: when it starts and ends
Mosquito months in Deuel County
In a normal year mosquito season in Deuel County, SD starts around May 3 and ends around October 5, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Deuel County, and when
- Start tipping out standing water weekly by April 19.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 5.
- 5 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.
Deuel County against the rest of SD
Deuel County has the 57th longest season of 66 SD counties, at 155 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 42.4°F.
- Day County: May 2 to October 6 (157 days, 10 WNV)
- Edmunds County: May 2 to October 5 (156 days, 10 WNV)
- Hamlin County: May 3 to October 5 (155 days, 12 WNV)
- Lyman County: May 3 to October 5 (155 days, 4 WNV)
West Nile in Deuel County
From 1999 to 2025, CDC ArboNET counted 11 human West Nile cases in Deuel County (3 neuroinvasive) across 9 years. The worst was 2023 with 2; the latest was 2023.
Background: reading the West Nile counts; how the dates are worked out.