Mosquito season in Pettis County, MO: when it starts and ends
Mosquito months in Pettis County
In a normal year mosquito season in Pettis County, MO starts around April 5 and ends around October 30, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Pettis 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 30.
- No West Nile cases since 2016, so bites in Pettis County are a nuisance; check window screens.
Pettis County against the rest of MO
Pettis County has the 76th longest season of 115 MO counties, at 208 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 54°F.
- Oregon County: April 5 to October 30 (208 days, 1 WNV)
- Perry County: April 5 to October 30 (208 days, 0 WNV)
- Callaway County: April 4 to October 28 (207 days, 0 WNV)
- Macon County: April 5 to October 29 (207 days, 0 WNV)
West Nile in Pettis County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Pettis County (1 neuroinvasive) across 2 years. The worst was 2015 with 1; the latest was 2015.
See how the dates are worked out, and when the season starts across the US.