United States, San Francisco

Monday

Today

Low

Tuesday

Tomorrow

Moderate

Wednesday

Jun 18

High

Thursday

Jun 19

High

Friday

Jun 20

Moderate

How we forecast?

San Francisco Mosquito Forecast: What to Expect

If you're planning outdoor activities near the iconic Golden Gate Park or the Embarcadero, understanding the San Francisco mosquito forecast is essential. Mosquito activity here tends to peak during the warm summer months, particularly July and August, when the forecast rates climb to 8 out of 10. Cooler months like December and January see minimal mosquito presence, with forecasts as low as 2. This seasonal trend means locals and visitors alike should be prepared during late spring through early fall. For up-to-date forecasts, the California Department of Public Health offers reliable resources to help you plan your outings with fewer mosquito nuisances.

Year round mosquito forecast

Mosquito Intensity

Factors Driving Mosquito Activity in San Francisco

San Francisco's unique microclimates and foggy conditions significantly influence mosquito populations. Unlike many cities, the cool coastal breezes and frequent fog can suppress mosquito breeding. However, urban water sources such as storm drains, fountains, and even neglected containers in neighborhoods like the Mission District provide perfect breeding grounds. Key influencers include:

Temperature: Warmer temperatures boost mosquito development.
Standing Water: Essential for larvae growth.
Humidity: Higher humidity supports adult mosquito survival.

Understanding these factors helps residents manage mosquito risks effectively. For tips on reducing breeding sites, visit the San Francisco Department of Public Health.

Mosquito-Borne Diseases to Watch in San Francisco

While San Francisco is not a hotspot for many mosquito-borne illnesses, vigilance is still important. The primary concern in the area is West Nile Virus, transmitted by local Culex mosquitoes. Cases are sporadic but have been reported near wetlands such as the Don Edwards San Francisco Bay National Wildlife Refuge. Travelers should also be aware of diseases common in other parts of California, like Zika and dengue, especially if visiting or returning from tropical regions. Preventive measures include:

Using EPA-approved insect repellents.
Wearing long sleeves and pants during dusk and dawn.
Eliminating standing water around your home.

More information is available at the CDC's West Nile Virus page.

Staying Updated and Prepared in San Francisco

To stay ahead of mosquito-related risks, locals and visitors should subscribe to alerts from local health departments and use apps that provide real-time mosquito activity updates. Regularly inspect your property, especially after rain, to remove stagnant water. When enjoying outdoor events like the San Francisco Fleet Week, carry mosquito repellent and wear protective clothing. Remember, mosquito control is a community effort, so encourage neighbors to participate in prevention. For continuous updates, check the Mosquito and Vector Control Association of California. Stay protected and enjoy San Francisco’s beauty safely. Stay informed with the San Francisco mosquito forecast. Learn about mosquito activity, diseases, and how to stay protected year-round.

Check out our recommended mosquito protection products

Mosquito-borne diseases in the area

Malaria

Zika

Dengue

Yellow Fever

Chikungunya

West Nile Fever

FAQs

Mosquito season generally runs from late spring through early fall, with peak activity in July and August.

West Nile Virus is the primary mosquito-borne disease reported in San Francisco, though cases are relatively rare.

Use insect repellent, wear long sleeves and pants during peak mosquito hours, and remove standing water around your home.

Further information

California Department of Public HealthSan Francisco Department of Public HealthCDC West Nile Virus