Mosquito season in Hancock County, OH: when it starts and ends
Mosquito months in Hancock County
In a normal year mosquito season in Hancock County, OH starts around April 12 and ends around October 27, about 28 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Hancock County, and when
- Start tipping out standing water weekly by March 29.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 27.
- 4 West Nile cases since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.
Hancock County against the rest of OH
Hancock County has the 17th longest season of 88 OH counties, at 199 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 52.3°F.
- Pike County: April 9 to October 28 (202 days, 0 WNV)
- Clermont County: April 11 to October 27 (199 days, 6 WNV)
- Jackson County: April 9 to October 24 (198 days, 0 WNV)
- Union County: April 10 to October 26 (198 days, 0 WNV)
West Nile in Hancock County
From 1999 to 2025, CDC ArboNET counted 15 human West Nile cases in Hancock County (9 neuroinvasive) across 10 years. The worst was 2017 with 2; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.