Mosquito season in Brown County, OH: when it starts and ends
Mosquito months in Brown County
In a normal year mosquito season in Brown County, OH starts around April 20 and ends around October 21, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Brown County, and when
- Start tipping out standing water weekly by April 6.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 21.
- No West Nile cases since 2016, so bites in Brown County are a nuisance; check window screens.
Brown County against the rest of OH
Brown County has the 77th longest season of 88 OH counties, at 184 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 52.4°F.
- Columbiana County: April 20 to October 22 (185 days, 3 WNV)
- Adams County: April 20 to October 21 (184 days, 0 WNV)
- Summit County: April 20 to October 21 (184 days, 7 WNV)
- Mahoning County: April 20 to October 20 (183 days, 3 WNV)
West Nile in Brown County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Brown County (2 neuroinvasive) across 2 years. The worst was 2015 with 1; the latest was 2015.
See how the dates are worked out, and when the season starts across the US.