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

Mosquito months in Elbert County

In a normal year mosquito season in Elbert County, CO starts around May 2 and ends around October 11, about 23 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 Elbert County, and when

• Start tipping out standing water weekly by April 18.
• Book any yard treatment for early May, ahead of the July peak.
• Repellent can go away after October 11.
• 6 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.

Elbert County against the rest of CO

Elbert County has the 27th longest season of 64 CO counties, at 162 days against 200 in Mesa County and 69 in Summit County. Its mean temperature is 48°F.

• Phillips County: May 1 to October 12 (164 days, 3 WNV)
• Lincoln County: May 1 to October 10 (162 days, 2 WNV)
• Adams County: May 2 to October 10 (161 days, 146 WNV)
• Arapahoe County: May 2 to October 10 (161 days, 113 WNV)

West Nile in Elbert County

From 1999 to 2025, CDC ArboNET counted 17 human West Nile cases in Elbert County (6 neuroinvasive) across 6 years. The worst was 2003 with 8; the latest was 2023.

See how the dates are worked out, and reading the West Nile counts.