Mosquito season in Conejos County, CO: when it starts and ends
Mosquito months in Conejos County
In a normal year mosquito season in Conejos County, CO starts around May 13 and ends around September 29, about 20 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Conejos County, and when
- Start tipping out standing water weekly by April 29.
- Book any yard treatment for mid May, ahead of the July peak.
- Repellent can go away after September 29.
- No West Nile cases since 2016, so bites in Conejos County are a nuisance; check window screens.
Conejos County against the rest of CO
Conejos County has the 37th longest season of 64 CO counties, at 139 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 42°F.
- Jefferson County: May 13 to October 2 (142 days, 132 WNV)
- Costilla County: May 13 to September 30 (140 days, 1 WNV)
- Saguache County: May 15 to September 28 (137 days, 1 WNV)
- Alamosa County: May 16 to September 27 (134 days, 2 WNV)
West Nile in Conejos County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Conejos County (0 neuroinvasive) across 1 year. The worst was 2003 with 1; the latest was 2003.
Background: when the season starts across the US; how the dates are worked out.