Mosquito season in Moffat County, CO: when it starts and ends
Mosquito months in Moffat County
In a normal year mosquito season in Moffat County, CO starts around June 1 and ends around September 19, about 16 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Moffat County, and when
- Start tipping out standing water weekly by May 18.
- Book any yard treatment for early June, ahead of the July peak.
- Repellent can go away after September 19.
- No West Nile cases since 2016, so bites in Moffat County are a nuisance; check window screens.
Moffat County against the rest of CO
Moffat County has the 50th longest season of 64 CO counties, at 110 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 43°F.
- Custer County: May 28 to September 20 (115 days, 1 WNV)
- Eagle County: May 31 to September 18 (110 days, 1 WNV)
- Garfield County: June 4 to September 20 (108 days, 2 WNV)
- Grand County: June 4 to September 15 (102 days, 3 WNV)
West Nile in Moffat County
From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Moffat County (0 neuroinvasive) across 2 years. The worst was 2003 with 2; the latest was 2010.
More: how the dates are worked out · when the season starts across the US.