Mosquito season in Harding County, SD: when it starts and ends
Mosquito months in Harding County
In a normal year mosquito season in Harding County, SD starts around May 5 and ends around October 5, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Harding County, and when
- Start tipping out standing water weekly by April 21.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 5.
- No West Nile cases since 2016, so bites in Harding County are a nuisance; check window screens.
Harding County against the rest of SD
Harding County has the 62nd longest season of 66 SD counties, at 152 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 44.5°F.
- Fall River County: May 5 to October 7 (155 days, 1 WNV)
- McPherson County: May 4 to October 3 (152 days, 4 WNV)
- Meade County: May 6 to October 3 (150 days, 7 WNV)
- Hughes County: May 8 to October 2 (147 days, 24 WNV)
West Nile in Harding County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Harding County (3 neuroinvasive) across 3 years. The worst was 2003 with 4; the latest was 2014.
Background: when mosquitoes go away for the winter; how the dates are worked out.