Mosquito season in Montgomery County, OH: when it starts and ends
Mosquito months in Montgomery County
In a normal year mosquito season in Montgomery County, OH starts around April 6 and ends around October 29, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Montgomery County, and when
- Start tipping out standing water weekly by March 23.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 29.
- 14 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check OH spray notices.
Montgomery County against the rest of OH
Montgomery County has the 7th longest season of 88 OH counties, at 206 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 53.7°F.
- Washington County: April 6 to October 29 (207 days, 0 WNV)
- Scioto County: April 7 to October 31 (207 days, 0 WNV)
- Ross County: April 6 to October 29 (206 days, 3 WNV)
- Warren County: April 6 to October 29 (206 days, 3 WNV)
West Nile in Montgomery County
From 1999 to 2025, CDC ArboNET counted 43 human West Nile cases in Montgomery County (27 neuroinvasive) across 13 years. The worst was 2012 with 14; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.