Mosquito season in El Paso County, CO: when it starts and ends
Mosquito months in El Paso County
In a normal year mosquito season in El Paso County, CO starts around April 24 and ends around October 15, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in El Paso County, and when
- Start tipping out standing water weekly by April 10.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 15.
- 66 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to July, and check CO spray notices.
El Paso County against the rest of CO
El Paso County has the 13th longest season of 64 CO counties, at 174 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 49.8°F.
- Crowley County: April 23 to October 16 (176 days, 2 WNV)
- Kit Carson County: April 27 to October 19 (175 days, 7 WNV)
- Delta County: April 25 to October 16 (174 days, 111 WNV)
- Washington County: April 27 to October 16 (172 days, 6 WNV)
West Nile in El Paso County
From 1999 to 2025, CDC ArboNET counted 201 human West Nile cases in El Paso County (78 neuroinvasive) across 17 years. The worst was 2003 with 114; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.