When Does Mosquito Season Start in California?

If you’re used to living somewhere with actual winters—the sort where you have to get out a parka to go to the mailbox—then California’s mosquito season will probably confuse you. Because the short answer is that it never really stops.

Most of the country deals with mosquitoes from late spring through early fall. Then the temperatures drop, mosquito activity shuts down, and everyone enjoys some much needed relief until the next year. But California doesn’t work that way, especially not in Pasadena.

We don’t see hard freezes in Southern California. And that’s what usually knocks out mosquito populations in other states. Temperatures rarely go below 40 even in the winter. That’s warm enough for some mosquito species to stay active and it’s definitely warm enough for eggs and larvae to survive until the weather takes a turn for the warmer again.

Mosquito activity does slow down in the cooler months, don’t get us wrong. It just doesn’t stop. And the moment nightly lows creep back above 50—which can happen any month of the year—mosquitoes start breeding all over again.

When is peak mosquito season in Pasadena?

Even though mosquitoes are always a problem to some degree in Pasadena, you’ll notice that it’s worse in warmer months. Around here, the worst mosquito problems tend to happen between March and November. That’s when temperatures consistently stay in the range mosquitoes love the most: between 80 and 90 degrees.

Spring is when mosquito activity really ramps up. Temperatures begin to warm and people start to water their yards more. All that irrigation makes patches of standing water, and that combined with the heat, is an open invitation to mosquitoes to start breeding.

Activity will then stay high through the summer and into the fall. As temperatures cool down in late November and December, you start to feel some relief again. But it’s not like flipping a switch on or off. Some species keep breeding as long as standing water and mild temperatures stick around.

What does this mean for Pasadena mosquito control?

If you’re waiting for mosquito season to “start” so you can begin treating your yard, then you’re already at risk of falling behind the mosquitoes. The trick with mosquito control, especially in a warm climate like Pasadena, is being proactive. Swatting every single mosquito is a nearly impossible task, so that’s why good pest control focuses on preventing the mosquitoes from being born in the first place.

At Mosquito Squad of Pasadena, we recommend starting treatments in early spring—February or March—before mosquito populations peak. Our Barrier Treatment Plus reduces mosquito populations by up to 90% and provides protection for up to 21 days.

We return every three weeks throughout the active season to help you maintain that protection. And for some properties where the mosquito pressure never lets up, that means treating well into November or even December depending on the weather.

Ready to protect your Pasadena property before mosquito activity peaks? Call Mosquito Squad of Pasadena at (213) 238-5564 or contact us online for a free assessment and quote.

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