Why are mosquitoes swarming the Sacramento area?

The recent rainfall in October and warmer temperatures have created ideal breeding conditions for mosquitoes, leading to a population boom in the Sacramento area.

How are Placer County residents being affected by the mosquito surge?

Residents like Violet Marshall and Molly Willing have reported being "eaten alive" by mosquitoes, with Violet's daughter even coming home from school events covered in bites.

When will the mosquito activity in Sacramento decrease?

According to Jake Hartle of the Placer County Vector Control District, as temperatures drop this November, the mosquito activity is expected to decrease, providing relief to residents.

Home / Weather / Mosquito Swarm Bites Californians as Temperatures Rise

Mosquito Swarm Bites Californians as Temperatures Rise

11 Nov

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Summary

Mosquito population boom due to October rain and warm weather
Invasive mosquitoes breeding in backyards and urban areas
Residents reporting severe bites and being "eaten alive"

Mosquito Swarm Bites Californians as Temperatures Rise

As of November 11th, 2025, residents in the Sacramento area have been dealing with a significant increase in mosquito activity, with many reporting being "eaten alive" by the biting insects. According to Jake Hartle, the deputy general manager of the Placer County Vector Control District, the recent weather conditions have created the perfect storm for a mosquito population boom.

The heavy rainfall in October, followed by warmer temperatures, has led to the formation of standing water, which serves as a breeding ground for mosquitoes. Additionally, the rain has caused an influx of invasive mosquito species to develop in people's backyards, thriving in even small amounts of water, such as a bottle cap.

Furthermore, agricultural mosquitoes have moved into urban areas to seek shelter for the winter while crops are being harvested. Hartle explains that these factors have resulted in "all kinds of conditions right now for maybe two or three different types of species to be able to provide this biting pressure."