Mosquito season in Clay County, KS: when it starts and ends
Mosquito months in Clay County
In a normal year mosquito season in Clay County, KS starts around April 9 and ends around October 28, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Clay County, and when
- Start tipping out standing water weekly by March 26.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 28.
- 2 West Nile cases since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.
Clay County against the rest of KS
Clay County has the 57th longest season of 105 KS counties, at 202 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 54.4°F.
- Doniphan County: April 8 to October 27 (202 days, 1 WNV)
- Mitchell County: April 8 to October 27 (202 days, 2 WNV)
- Gray County: April 10 to October 29 (202 days, 10 WNV)
- Ottawa County: April 10 to October 29 (202 days, 0 WNV)
West Nile in Clay County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Clay County (4 neuroinvasive) across 5 years. The worst was 2003 with 2; the latest was 2025.
Background: when the season starts across the US; how the dates are worked out.