Mosquito season in Blaine County, ID: when it starts and ends
Mosquito months in Blaine County
In a normal year mosquito season in Blaine County, ID starts around June 7 and ends around September 21, about 15 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Blaine County, and when
- Start tipping out standing water weekly by May 24.
- Book any yard treatment for early June, ahead of the July peak.
- Repellent can go away after September 21.
- No West Nile cases since 2016, so bites in Blaine County are a nuisance; check window screens.
Blaine County against the rest of ID
Blaine County has the 41st longest season of 44 ID counties, at 106 days against 194 in Canyon County and 85 in Fremont County. Its mean temperature is 41.4°F.
- Custer County: June 2 to September 18 (107 days, 0 WNV)
- Idaho County: May 24 to September 7 (106 days, 0 WNV)
- Adams County: June 1 to September 9 (100 days, 2 WNV)
- Lemhi County: June 10 to September 4 (86 days, 2 WNV)
West Nile in Blaine County
From 1999 to 2025, CDC ArboNET counted 11 human West Nile cases in Blaine County (1 neuroinvasive) across 2 years. The worst was 2006 with 10; the latest was 2014.
Background: when mosquitoes go away for the winter; how the dates are worked out.