Mosquito season in Washington County, KS: when it starts and ends
Mosquito months in Washington County
In a normal year mosquito season in Washington County, KS starts around April 14 and ends around October 23, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Washington County, and when
- Start tipping out standing water weekly by March 31.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 23.
- 2 West Nile cases since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.
Washington County against the rest of KS
Washington County has the 81st longest season of 105 KS counties, at 192 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 52.8°F.
- Barton County: April 14 to October 25 (194 days, 8 WNV)
- Morton County: April 16 to October 26 (193 days, 1 WNV)
- Marshall County: April 14 to October 22 (191 days, 2 WNV)
- Phillips County: April 15 to October 23 (191 days, 1 WNV)
West Nile in Washington County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Washington County (4 neuroinvasive) across 5 years. The worst was 2018 with 1; the latest was 2018.
More: how the dates are worked out · when mosquitoes go away for the winter.