Mosquito season in Hamilton County, KS: when it starts and ends
Mosquito months in Hamilton County
In a normal year mosquito season in Hamilton County, KS starts around April 21 and ends around October 19, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Hamilton County, and when
- Start tipping out standing water weekly by April 7.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 19.
- 3 West Nile cases since 2016 (last 2023): you should use repellent at dusk June to August, more so if over 60.
Hamilton County against the rest of KS
Hamilton County has the 99th longest season of 105 KS counties, at 181 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 53.4°F.
- Norton County: April 21 to October 21 (183 days, 4 WNV)
- Cheyenne County: April 20 to October 18 (181 days, 2 WNV)
- Rush County: April 21 to October 19 (181 days, 0 WNV)
- Wichita County: April 23 to October 21 (181 days, 0 WNV)
West Nile in Hamilton County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Hamilton County (2 neuroinvasive) across 5 years. The worst was 2023 with 1; the latest was 2023.
See how the dates are worked out, and when mosquitoes go away for the winter.