Mosquito season in Park County, CO: when it starts and ends
Mosquito months in Park County
In a normal year mosquito season in Park County, CO starts around June 15 and ends around September 8, about 12 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Park County, and when
- Start tipping out standing water weekly by June 1.
- Book any yard treatment for mid June, ahead of the July peak.
- Repellent can go away after September 8.
- No West Nile cases since 2016, so bites in Park County are a nuisance; check window screens.
Park County against the rest of CO
Park County has the 61st longest season of 64 CO counties, at 85 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 36.4°F.
- Gilpin County: June 12 to September 7 (87 days, 0 WNV)
- Gunnison County: June 14 to September 8 (86 days, 1 WNV)
- Lake County: June 13 to September 3 (82 days, 0 WNV)
- San Juan County: June 22 to September 7 (77 days, 0 WNV)
West Nile in Park County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Park County (0 neuroinvasive) across 2 years. The worst was 2004 with 1; the latest was 2004.
See how the dates are worked out, and when mosquitoes go away for the winter.