Mosquito season in Mahoning County, OH: when it starts and ends

Mosquito months in Mahoning County

In a normal year mosquito season in Mahoning County, OH starts around April 20 and ends around October 20, about 26 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Mahoning 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 20.
• 3 West Nile cases since 2016 (last 2021): you should use repellent at dusk July to July, more so if over 60.

Mahoning County against the rest of OH

Mahoning County has the 79th longest season of 88 OH counties, at 183 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 49.6°F.

• Brown County: April 20 to October 21 (184 days, 0 WNV)
• Summit County: April 20 to October 21 (184 days, 7 WNV)
• Holmes County: April 21 to October 21 (183 days, 3 WNV)
• Williams County: April 21 to October 20 (182 days, 1 WNV)

West Nile in Mahoning County

From 1999 to 2025, CDC ArboNET counted 11 human West Nile cases in Mahoning County (8 neuroinvasive) across 7 years. The worst was 2002 with 3; the latest was 2021.

Background: when mosquitoes go away for the winter; how the dates are worked out.