Mosquito season in Grant County, KS: when it starts and ends
Mosquito months in Grant County
In a normal year mosquito season in Grant County, KS starts around April 16 and ends around October 24, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Grant County, and when
- Start tipping out standing water weekly by April 2.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 24.
- 5 West Nile cases since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.
Grant County against the rest of KS
Grant County has the 84th longest season of 105 KS counties, at 191 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 54.2°F.
- Marshall County: April 14 to October 22 (191 days, 2 WNV)
- Phillips County: April 15 to October 23 (191 days, 1 WNV)
- Finney County: April 17 to October 25 (191 days, 7 WNV)
- Lincoln County: April 17 to October 23 (189 days, 1 WNV)
West Nile in Grant County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Grant County (4 neuroinvasive) across 3 years. The worst was 2023 with 4; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.