Mosquito season in Otero County, CO: when it starts and ends
Mosquito months in Otero County
In a normal year mosquito season in Otero County, CO starts around April 29 and ends around October 11, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Otero County, and when
- Start tipping out standing water weekly by April 15.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 11.
- 12 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check CO spray notices.
Otero County against the rest of CO
Otero County has the 23rd longest season of 64 CO counties, at 165 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 52.5°F.
- Yuma County: April 29 to October 15 (169 days, 3 WNV)
- Dolores County: May 2 to October 15 (166 days, 0 WNV)
- Douglas County: May 1 to October 12 (164 days, 49 WNV)
- Phillips County: May 1 to October 12 (164 days, 3 WNV)
West Nile in Otero County
From 1999 to 2025, CDC ArboNET counted 69 human West Nile cases in Otero County (18 neuroinvasive) across 15 years. The worst was 2003 with 28; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.