Mosquito season in Lake County, CA: when it starts and ends
Mosquito months in Lake County
In a normal year mosquito season in Lake County, CA starts around March 14 and ends around November 17, about 35 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lake County, and when
- Start tipping out standing water weekly by February 28.
- Book any yard treatment for mid March, ahead of the July peak.
- Repellent can go away after November 17.
- 10 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check CA spray notices.
Lake County against the rest of CA
Lake County has the 40th longest season of 58 CA counties, at 247 days against 365 in Los Angeles County and 110 in Mono County. Its mean temperature is 58.2°F.
- Monterey County: March 12 to November 22 (255 days, 5 WNV)
- San Benito County: March 12 to November 22 (255 days, 0 WNV)
- San Diego County: March 14 to November 14 (245 days, 36 WNV)
- Inyo County: March 31 to November 12 (226 days, 4 WNV)
West Nile in Lake County
From 1999 to 2025, CDC ArboNET counted 17 human West Nile cases in Lake County (9 neuroinvasive) across 9 years. The worst was 2023 with 6; the latest was 2023.
See how the dates are worked out, and reading the West Nile counts.