Mosquito season in Huerfano County, CO: when it starts and ends

Mosquito months in Huerfano County

In a normal year mosquito season in Huerfano County, CO starts around April 29 and ends around October 15, about 24 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Huerfano 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 15.
• 2 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.

Huerfano County against the rest of CO

Huerfano County has the 20th longest season of 64 CO counties, at 169 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 50.5°F.

• Montezuma County: April 30 to October 17 (170 days, 10 WNV)
• Cheyenne County: April 28 to October 14 (169 days, 0 WNV)
• Yuma County: April 29 to October 15 (169 days, 3 WNV)
• Dolores County: May 2 to October 15 (166 days, 0 WNV)

West Nile in Huerfano County

From 1999 to 2025, CDC ArboNET counted 15 human West Nile cases in Huerfano County (4 neuroinvasive) across 6 years. The worst was 2003 with 10; the latest was 2023.

See how the dates are worked out, and when mosquitoes go away for the winter.