Mosquito season in Putnam County, MO: when it starts and ends
Mosquito months in Putnam County
In a normal year mosquito season in Putnam County, MO starts around April 13 and ends around October 22, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Putnam County, and when
- Start tipping out standing water weekly by March 30.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 22.
- No West Nile cases since 2016, so bites in Putnam County are a nuisance; check window screens.
Putnam County against the rest of MO
Putnam County has the 110th longest season of 115 MO counties, at 192 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 50.9°F.
- Atchison County: April 11 to October 22 (193 days, 0 WNV)
- Gasconade County: April 14 to October 24 (193 days, 0 WNV)
- Scotland County: April 13 to October 22 (192 days, 0 WNV)
- Mercer County: April 14 to October 23 (192 days, 0 WNV)
West Nile in Putnam County
CDC ArboNET lists no human West Nile cases for Putnam County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 3 of those years.
Background: when the season starts across the US; how the dates are worked out.