Mosquito season in Del Norte County, CA: when it starts and ends
Mosquito months in Del Norte County
In a normal year mosquito season in Del Norte County, CA starts around April 5 and ends around November 2, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Del Norte County, and when
- Start tipping out standing water weekly by March 22.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after November 2.
- No West Nile cases since 2016, so bites in Del Norte County are a nuisance; check window screens.
Del Norte County against the rest of CA
Del Norte County has the 47th longest season of 58 CA counties, at 211 days against 365 in Los Angeles County and 110 in Mono County. Its mean temperature is 53.2°F.
- Mariposa County: April 4 to November 8 (217 days, 0 WNV)
- Mendocino County: March 31 to October 30 (213 days, 0 WNV)
- Trinity County: April 11 to October 29 (201 days, 0 WNV)
- El Dorado County: April 15 to October 29 (197 days, 6 WNV)
West Nile in Del Norte County
CDC ArboNET lists no human West Nile cases for Del Norte County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 2 of those years.
Background: when mosquitoes go away for the winter; how the dates are worked out.