Mosquito season in Tripp County, SD: when it starts and ends
Mosquito months in Tripp County
In a normal year mosquito season in Tripp County, SD starts around April 22 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Tripp County, and when
- Start tipping out standing water weekly by April 8.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 18.
- 4 West Nile cases since 2016 (last 2021): you should use repellent at dusk July to August, more so if over 60.
Tripp County against the rest of SD
Tripp County has the 2nd longest season of 66 SD counties, at 179 days against 179 in Yankton County and 139 in Lawrence County. Its mean temperature is 49.8°F.
- Yankton County: April 21 to October 16 (179 days, 20 WNV)
- Douglas County: April 21 to October 16 (178 days, 11 WNV)
- Charles Mix County: April 22 to October 17 (178 days, 18 WNV)
West Nile in Tripp County
From 1999 to 2025, CDC ArboNET counted 36 human West Nile cases in Tripp County (6 neuroinvasive) across 14 years. The worst was 2003 with 14; the latest was 2021.
Background: reading the West Nile counts; how the dates are worked out.