Mosquito season in Ralls County, MO: when it starts and ends
Mosquito months in Ralls County
In a normal year mosquito season in Ralls County, MO starts around April 7 and ends around October 28, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Ralls County, and when
- Start tipping out standing water weekly by March 24.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 28.
- No West Nile cases since 2016, so bites in Ralls County are a nuisance; check window screens.
Ralls County against the rest of MO
Ralls County has the 83rd longest season of 115 MO counties, at 204 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 53°F.
- Marion County: April 6 to October 28 (205 days, 1 WNV)
- Shannon County: April 6 to October 28 (205 days, 1 WNV)
- Clay County: April 8 to October 27 (202 days, 4 WNV)
- Lewis County: April 8 to October 27 (202 days, 0 WNV)
West Nile in Ralls County
CDC ArboNET lists no human West Nile cases for Ralls County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 5 of those years.
See how the dates are worked out, and when mosquitoes go away for the winter.