Mosquito season in Lewis County, ID: when it starts and ends
Mosquito months in Lewis County
In a normal year mosquito season in Lewis County, ID starts around May 13 and ends around October 4, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lewis County, and when
- Start tipping out standing water weekly by April 29.
- Book any yard treatment for mid May, ahead of the August peak.
- Repellent can go away after October 4.
- 1 West Nile case since 2016 (last 2016): you should use repellent at dusk August, more so if over 60.
Lewis County against the rest of ID
Lewis County has the 26th longest season of 44 ID counties, at 144 days against 194 in Canyon County and 85 in Fremont County. Its mean temperature is 45.5°F.
- Madison County: May 5 to October 3 (151 days, 0 WNV)
- Shoshone County: May 8 to September 30 (145 days, 0 WNV)
- Clark County: May 10 to September 30 (143 days, 0 WNV)
- Butte County: May 13 to October 1 (141 days, 0 WNV)
West Nile in Lewis County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Lewis County (2 neuroinvasive) across 2 years. The worst was 2016 with 1; the latest was 2016.
More: how the dates are worked out · when the season starts across the US.