Mosquito season in Campbell County, SD: when it starts and ends
Mosquito months in Campbell County
In a normal year mosquito season in Campbell County, SD starts around May 1 and ends around October 6, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Campbell 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 6.
- 3 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.
Campbell County against the rest of SD
Campbell County has the 50th longest season of 66 SD counties, at 158 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 43.3°F.
- Butte County: May 2 to October 8 (159 days, 3 WNV)
- Brookings County: May 1 to October 6 (158 days, 27 WNV)
- Faulk County: May 1 to October 6 (158 days, 14 WNV)
- Stanley County: May 1 to October 5 (157 days, 4 WNV)
West Nile in Campbell County
From 1999 to 2025, CDC ArboNET counted 13 human West Nile cases in Campbell County (2 neuroinvasive) across 7 years. The worst was 2003 with 6; the latest was 2023.
Background: when the season starts across the US; how the dates are worked out.