Mosquito season in Saguache County, CO: when it starts and ends
Mosquito months in Saguache County
In a normal year mosquito season in Saguache County, CO starts around May 15 and ends around September 28, about 20 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Saguache County, and when
- Start tipping out standing water weekly by May 1.
- Book any yard treatment for mid May, ahead of the July peak.
- Repellent can go away after September 28.
- 1 West Nile case since 2016 (last 2023): you should use repellent at dusk July, more so if over 60.
Saguache County against the rest of CO
Saguache County has the 38th longest season of 64 CO counties, at 137 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 41.8°F.
- Costilla County: May 13 to September 30 (140 days, 1 WNV)
- Conejos County: May 13 to September 29 (139 days, 0 WNV)
- Alamosa County: May 16 to September 27 (134 days, 2 WNV)
- Rio Grande County: May 19 to September 26 (130 days, 1 WNV)
West Nile in Saguache County
From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Saguache County (0 neuroinvasive) across 3 years. The worst was 2003 with 2; the latest was 2023.
See how the dates are worked out, and when the season starts across the US.