Mosquito season in Montezuma County, CO: when it starts and ends
Mosquito months in Montezuma County
In a normal year mosquito season in Montezuma County, CO starts around April 30 and ends around October 17, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Montezuma County, and when
- Start tipping out standing water weekly by April 16.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 17.
- 10 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check CO spray notices.
Montezuma County against the rest of CO
Montezuma County has the 18th longest season of 64 CO counties, at 170 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 50.8°F.
- Morgan County: April 27 to October 15 (171 days, 23 WNV)
- Sedgwick County: April 27 to October 14 (170 days, 4 WNV)
- Cheyenne County: April 28 to October 14 (169 days, 0 WNV)
- Huerfano County: April 29 to October 15 (169 days, 2 WNV)
West Nile in Montezuma County
From 1999 to 2025, CDC ArboNET counted 29 human West Nile cases in Montezuma County (12 neuroinvasive) across 7 years. The worst was 2013 with 6; the latest was 2023.
Background: reading the West Nile counts; how the dates are worked out.