Mosquito season in Perkins County, SD: when it starts and ends
Mosquito months in Perkins County
In a normal year mosquito season in Perkins County, SD starts around May 1 and ends around October 9, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Perkins County, and when
- Start tipping out standing water weekly by April 17.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 9.
- 1 West Nile case since 2016 (last 2023): you should use repellent at dusk July to August, more so if over 60.
Perkins County against the rest of SD
Perkins County has the 33rd longest season of 66 SD counties, at 161 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 45.5°F.
- Roberts County: April 29 to October 8 (162 days, 5 WNV)
- Kingsbury County: April 29 to October 8 (161 days, 17 WNV)
- Bennett County: May 2 to October 10 (161 days, 1 WNV)
- Hyde County: May 2 to October 10 (161 days, 1 WNV)
West Nile in Perkins County
From 1999 to 2025, CDC ArboNET counted 28 human West Nile cases in Perkins County (1 neuroinvasive) across 6 years. The worst was 2003 with 18; the latest was 2023.
See how the dates are worked out, and when the season starts across the US.