Mosquito season in Weber County, UT: when it starts and ends
Mosquito months in Weber County
In a normal year mosquito season in Weber County, UT starts around May 5 and ends around October 7, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Weber County, and when
- Start tipping out standing water weekly by April 21.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 7.
- 15 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July, and check UT spray notices.
Weber County against the rest of UT
Weber County has the 16th longest season of 29 UT counties, at 155 days against 210 in Salt Lake County and 82 in Summit County. Its mean temperature is 45.5°F.
- Box Elder County: April 30 to October 9 (162 days, 11 WNV)
- Juab County: May 2 to October 9 (160 days, 0 WNV)
- Emery County: May 4 to October 5 (154 days, 1 WNV)
- Millard County: May 7 to October 5 (151 days, 1 WNV)
West Nile in Weber County
From 1999 to 2025, CDC ArboNET counted 33 human West Nile cases in Weber County (22 neuroinvasive) across 13 years. The worst was 2006 with 10; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.