Mosquito season in Madison County, ID: when it starts and ends
Mosquito months in Madison County
In a normal year mosquito season in Madison County, ID starts around May 5 and ends around October 3, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Madison County, and when
- Start tipping out standing water weekly by April 21.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 3.
- No West Nile cases since 2016, so bites in Madison County are a nuisance; check window screens.
Madison County against the rest of ID
Madison County has the 24th longest season of 44 ID counties, at 151 days against 194 in Canyon County and 85 in Fremont County. Its mean temperature is 44°F.
- Bonner County: May 3 to October 1 (151 days, 0 WNV)
- Oneida County: May 4 to October 2 (151 days, 0 WNV)
- Shoshone County: May 8 to September 30 (145 days, 0 WNV)
- Lewis County: May 13 to October 4 (144 days, 1 WNV)
West Nile in Madison County
From 1999 to 2025, CDC ArboNET counted 9 human West Nile cases in Madison County (3 neuroinvasive) across 2 years. The worst was 2006 with 7; the latest was 2007.
More: how the dates are worked out · when mosquitoes go away for the winter.