Mosquito season in Marion County, KS: when it starts and ends
Mosquito months in Marion County
In a normal year mosquito season in Marion County, KS starts around March 30 and ends around November 3, about 31 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Marion County, and when
- Start tipping out standing water weekly by March 16.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 3.
- No West Nile cases since 2016, so bites in Marion County are a nuisance; check window screens.
Marion County against the rest of KS
Marion County has the 10th longest season of 105 KS counties, at 218 days against 227 in Cherokee County and 178 in Thomas County. Its mean temperature is 56.5°F.
- Allen County: March 30 to November 4 (219 days, 0 WNV)
- Harper County: March 31 to November 5 (219 days, 1 WNV)
- Woodson County: April 1 to November 4 (217 days, 1 WNV)
- Wilson County: April 1 to November 3 (216 days, 0 WNV)
West Nile in Marion County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Marion County (1 neuroinvasive) across 4 years. The worst was 2010 with 2; the latest was 2015.
Background: when mosquitoes go away for the winter; how the dates are worked out.