Mosquito season in Lake County, CO: when it starts and ends
Mosquito months in Lake County
In a normal year mosquito season in Lake County, CO starts around June 13 and ends around September 3, about 12 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lake County, and when
- Start tipping out standing water weekly by May 30.
- Book any yard treatment for mid June, ahead of the July peak.
- Repellent can go away after September 3.
- No West Nile cases since 2016, so bites in Lake County are a nuisance; check window screens.
Lake County against the rest of CO
Lake County has the 62nd longest season of 64 CO counties, at 82 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 35.6°F.
- Gunnison County: June 14 to September 8 (86 days, 1 WNV)
- Park County: June 15 to September 8 (85 days, 0 WNV)
- San Juan County: June 22 to September 7 (77 days, 0 WNV)
- Summit County: June 20 to August 28 (69 days, 2 WNV)
West Nile in Lake County
CDC ArboNET lists no human West Nile cases for Lake County from 1999 to 2025.
Background: when the season starts across the US; how the dates are worked out.