Mosquito season in Calaveras County, CA: when it starts and ends
Mosquito months in Calaveras County
In a normal year mosquito season in Calaveras County, CA starts around March 4 and ends around November 26, about 38 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Calaveras County, and when
- Start tipping out standing water weekly by February 18.
- Book any yard treatment for early March, ahead of the July peak.
- Repellent can go away after November 26.
- 2 West Nile cases since 2016 (last 2024): you should use repellent at dusk June to September, more so if over 60.
Calaveras County against the rest of CA
Calaveras County has the 34th longest season of 58 CA counties, at 267 days against 365 in Los Angeles County and 110 in Mono County. Its mean temperature is 60.1°F.
- Santa Barbara County: February 27 to November 27 (273 days, 2 WNV)
- San Luis Obispo County: February 22 to November 21 (272 days, 6 WNV)
- Glenn County: March 1 to November 22 (266 days, 18 WNV)
- Madera County: March 4 to November 25 (266 days, 37 WNV)
West Nile in Calaveras County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Calaveras County (4 neuroinvasive) across 4 years. The worst was 2005 with 2; the latest was 2024.
See how the dates are worked out, and when mosquitoes go away for the winter.