Mosquito season in Harper County, KS: when it starts and ends
Mosquito months in Harper County
In a normal year mosquito season in Harper County, KS starts around March 31 and ends around November 5, about 31 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Harper County, and when
- Start tipping out standing water weekly by March 17.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 5.
- 1 West Nile case since 2016 (last 2025): you should use repellent at dusk June to September, more so if over 60.
Harper County against the rest of KS
Harper County has the 9th longest season of 105 KS counties, at 219 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 57.4°F.
- Sedgwick County: March 30 to November 5 (220 days, 28 WNV)
- Allen County: March 30 to November 4 (219 days, 0 WNV)
- Marion County: March 30 to November 3 (218 days, 0 WNV)
- Woodson County: April 1 to November 4 (217 days, 1 WNV)
West Nile in Harper County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Harper County (4 neuroinvasive) across 5 years. The worst was 2010 with 2; the latest was 2025.
Background: when mosquitoes go away for the winter; how the dates are worked out.