Mosquito season in Madera County, CA: when it starts and ends
Mosquito months in Madera County
In a normal year mosquito season in Madera County, CA starts around March 4 and ends around November 25, about 38 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Madera 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 25.
- 37 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to September, and check CA spray notices.
Madera County against the rest of CA
Madera County has the 36th longest season of 58 CA counties, at 266 days against 365 in Los Angeles County and 110 in Mono County. Its mean temperature is 60.9°F.
- Calaveras County: March 4 to November 26 (267 days, 2 WNV)
- Glenn County: March 1 to November 22 (266 days, 18 WNV)
- Amador County: March 7 to November 23 (261 days, 3 WNV)
- Monterey County: March 12 to November 22 (255 days, 5 WNV)
West Nile in Madera County
From 1999 to 2025, CDC ArboNET counted 80 human West Nile cases in Madera County (50 neuroinvasive) across 18 years. The worst was 2005 with 18; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.