Mosquito season in Iron County, MO: when it starts and ends
Mosquito months in Iron County
In a normal year mosquito season in Iron County, MO starts around March 31 and ends around November 2, about 31 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Iron County, and when
- Start tipping out standing water weekly by March 17.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 2.
- No West Nile cases since 2016, so bites in Iron County are a nuisance; check window screens.
Iron County against the rest of MO
Iron County has the 36th longest season of 115 MO counties, at 216 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 55.1°F.
- Jefferson County: March 31 to November 3 (217 days, 3 WNV)
- Ripley County: March 31 to November 3 (217 days, 0 WNV)
- St. Charles County: March 31 to November 2 (216 days, 9 WNV)
- Ozark County: April 2 to November 4 (216 days, 0 WNV)
West Nile in Iron County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Iron County (1 neuroinvasive) across 1 year. The worst was 2009 with 1; the latest was 2009.
See how the dates are worked out, and when mosquitoes go away for the winter.