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Why Mosquito Season Might Be Milder in Southern California This Year

Four types of mosquitoes: Aedes albopictus, Aedes aegypti, Anopheles, Culex tarsalis, shown biting skin.

Southern California may experience a lighter mosquito season in 2025 due to dry weather conditions and below-average rainfall over the winter and spring. With fewer water sources available for mosquito breeding, experts anticipate lower initial mosquito populations across the region.

Dry conditions limit breeding sites, but mosquito activity may become more concentrated around available water sources. Residents should stay alert around homes and neighborhoods for potential hotspots, such as birdbaths, containers, gutters, and neglected swimming pools.

The regional mosquito season typically runs from June through mid-October:

  • Culex mosquitoes, which can carry West Nile virus, usually peak in June.
  • Aedes mosquitoes, known for spreading dengue, Zika, and malaria, tend to increase in August and September.

Disease Update (as of early June 2025):

  • No human cases of West Nile virus have been reported this year in California.
  • 33 travel-related dengue cases have been confirmed in the state, including:
    • 5 in Los Angeles County
    • 1 in Riverside County
    • 2 in San Bernardino County

In 2024, California recorded 723 dengue cases, the majority related to international travel — a significant rise from 250 cases in 2023.

Prevention Tips:

  • Eliminate any standing water on your property at least once a week.
  • Use EPA-registered insect repellents such as DEET, Picaridin, IR3535, or oil of lemon eucalyptus.
  • Wear long-sleeved shirts, long pants, and socks when outdoors, especially during peak mosquito hours.
  • Maintain window and door screens to keep mosquitoes out of indoor spaces.
  • Participate in local mosquito control programs if available — some areas may use sterile mosquito releases to reduce disease risk.

Mosquitoes can breed in as little as a teaspoon of water, especially container-breeding Aedes mosquitoes. Common sites include plant saucers, rain barrels, pet bowls, and even bottle caps. Staying proactive throughout the summer can protect both individuals and communities.

For more prevention resources, visit comptoncreekmad.org.

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