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

Mosquito months in Pickaway County

In a normal year mosquito season in Pickaway County, OH starts around April 5 and ends around October 31, about 30 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 Pickaway County, and when

• Start tipping out standing water weekly by March 22.
• Book any yard treatment for early April, ahead of the July peak.
• Repellent can go away after October 31.
• 1 West Nile case since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.

Pickaway County against the rest of OH

Pickaway County has the 2nd longest season of 88 OH counties, at 209 days against 209 in Gallia County and 177 in Ashtabula County. Its mean temperature is 54.1°F.

• Gallia County: April 4 to October 30 (209 days, 0 WNV)
• Greene County: April 5 to October 30 (208 days, 1 WNV)
• Hamilton County: April 5 to October 30 (208 days, 13 WNV)

West Nile in Pickaway County

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Pickaway County (0 neuroinvasive) across 2 years. The worst was 2025 with 1; the latest was 2025.

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