Mosquito season in Carbon County, UT: when it starts and ends
Mosquito months in Carbon County
In a normal year mosquito season in Carbon County, UT 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 Carbon 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.
- No West Nile cases since 2016, so bites in Carbon County are a nuisance; check window screens.
Carbon County against the rest of UT
Carbon County has the 10th longest season of 29 UT counties, at 174 days against 210 in Salt Lake County and 82 in Summit County. Its mean temperature is 49.7°F.
- Uintah County: April 19 to October 13 (177 days, 6 WNV)
- San Juan County: April 24 to October 17 (176 days, 2 WNV)
- Cache County: April 27 to October 12 (168 days, 22 WNV)
- Tooele County: April 28 to October 12 (167 days, 0 WNV)
West Nile in Carbon County
From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Carbon County (1 neuroinvasive) across 2 years. The worst was 2006 with 3; the latest was 2006.
Background: when mosquitoes go away for the winter; how the dates are worked out.