California's early mosquito surge sparks health warnings ahead of summer

California state officials are sounding the alarm over an early mosquito season due to an uncharacteristically warm winter, leading to an explosion in population.

The announcement comes in accordance with California Mosquito Awareness Week, when vector control officials seek to alert the public over the health threat that mosquitoes pose and how they can prevent year-round breeding.

"You've heard of Shark Week, Mosquito Week is worse, because mosquitoes kill more people than any other animal on Earth," said Brian Brannon, with Orange County Vector Control. "We're really concerned; we want to get the word out to people."

Officials say that peak mosquito season hasn't even yet, but the warm winter and brief period of abundant rain to start the year contributed to an early breeding season for the neighborhood nuisance that can carry viruses like West Nile, Dengue and Zika.

In the first few days of April, Orange County Vector Control officials say that they caught 43 mosquitoes per trap, more than two times the 17 mosquitoes trapped in the five-year average in that same time period.

The problem has spread throughout Southern California, including in the Los Angeles County city of El Segundo, where residents complained of a months-long nightmare beginning in late 2025, when there was an influx of mosquitoes at the Hyperion Water Reclamation Plant. In response, the county's vector control laid traps to help mitigate the problem.

Vector control officials advise that people walk their yards once a week to dump and drain standing water from buckets, containers and plant saucers, where mosquitoes typically lay their eggs. People are also advised to fix screens on windows and doors to keep mosquitoes from entering their homes and to have repellent ready.

"We're seeing a lot of mosquitoes," Bannon said. "We're seeing almost as many mosquitoes in one week as we saw in summer last year."

Despite this, Bannon says that the temperatures aren't high enough for West Nile virus to replicate in the wild, but with warmer weather incoming in weeks, he says people should be vigilant before it's too late.