Mosquito season in Summit County, OH: when it starts and ends
Mosquito months in Summit County
In a normal year mosquito season in Summit 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 Summit 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.
- 7 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to August, more so if over 60.
Summit County against the rest of OH
Summit County has the 78th longest season of 88 OH counties, at 184 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 50.3°F.
- Adams County: April 20 to October 21 (184 days, 0 WNV)
- Brown County: April 20 to October 21 (184 days, 0 WNV)
- Mahoning County: April 20 to October 20 (183 days, 3 WNV)
- Holmes County: April 21 to October 21 (183 days, 3 WNV)
West Nile in Summit County
From 1999 to 2025, CDC ArboNET counted 17 human West Nile cases in Summit County (12 neuroinvasive) across 9 years. The worst was 2002 with 5; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.