Mosquito season in Weston County, WY: when it starts and ends
Mosquito months in Weston County
In a normal year mosquito season in Weston County, WY starts around May 9 and ends around October 2, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Weston County, and when
- Start tipping out standing water weekly by April 25.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 2.
- No West Nile cases since 2016, so bites in Weston County are a nuisance; check window screens.
Weston County against the rest of WY
Weston County has the 7th longest season of 23 WY counties, at 146 days against 163 in Big Horn County and 75 in Teton County. Its mean temperature is 45.2°F.
- Sheridan County: May 8 to October 5 (150 days, 3 WNV)
- Converse County: May 8 to October 1 (146 days, 1 WNV)
- Goshen County: May 9 to October 1 (145 days, 15 WNV)
- Laramie County: May 9 to October 1 (145 days, 11 WNV)
West Nile in Weston County
From 1999 to 2025, CDC ArboNET counted 20 human West Nile cases in Weston County (4 neuroinvasive) across 5 years. The worst was 2003 with 11; the latest was 2014.
More: how the dates are worked out · when mosquitoes go away for the winter.