Mosquito season in Teton County, ID: when it starts and ends
Mosquito months in Teton County
In a normal year mosquito season in Teton County, ID starts around May 22 and ends around September 20, about 17 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Teton County, and when
- Start tipping out standing water weekly by May 8.
- Book any yard treatment for late May, ahead of the July peak.
- Repellent can go away after September 20.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July, more so if over 60.
Teton County against the rest of ID
Teton County has the 33rd longest season of 44 ID counties, at 121 days against 194 in Canyon County and 85 in Fremont County. Its mean temperature is 41.2°F.
- Bonneville County: May 19 to September 23 (127 days, 0 WNV)
- Clearwater County: May 18 to September 20 (125 days, 0 WNV)
- Valley County: May 30 to September 23 (116 days, 1 WNV)
- Bear Lake County: May 25 to September 16 (114 days, 0 WNV)
West Nile in Teton County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Teton County (0 neuroinvasive) across 2 years. The worst was 2007 with 4; the latest was 2018.
See how the dates are worked out, and when the season starts across the US.