Northwest Los Angeles’ Mediterranean climate boasts warm, dry summers and mild, wetter winters, creates an ideal environment for a variety of mosquito species. Urban density, ornamental landscaping, and small pockets of standing water all contribute to consistent mosquito presence throughout much of the year.
While more than 50 mosquito species are found across Southern California, only a few dominate residential and outdoor areas. These are the species most likely to affect outdoor comfort and activity from spring through late autumn.
Aedes aegypti has become one of the most widespread and problematic mosquito species across Los Angeles County. Known for its preference for human hosts, this small, black mosquito with white markings bites aggressively during daylight hours. It lays eggs in artificial containers such as flowerpots, gutters, and pet water bowls—thriving even in small amounts of water.
Recognizable by its bold black-and-white stripes, Aedes albopictus is highly adaptable and active during the day. This species has become increasingly common in the Los Angeles area over the past decade, often appearing in shaded yards, under decks, or around dense vegetation. It’s capable of surviving in both urban and suburban environments, making it a persistent nuisance during warmer months.
Most active from dusk through dawn, Culex quinquefasciatus is a key species in Los Angeles and one of the primary vectors of West Nile virus in Southern California. It breeds in stagnant water sources such as storm drains, irrigation runoff, and neglected swimming pools. Populations tend to spike following summer rain or overwatering events in residential landscapes.
This species prefers rural and semi-rural habitats but can occasionally be found in greenbelts or areas near the San Fernando Valley. Culex tarsalis is most active at dusk and dawn and is known to transmit both West Nile and Western equine encephalitis viruses.
