About the Air District

San Francisco County

Learn about San Francisco County - its climate, potential air pollution concerns, and current air quality. You can also view upcoming Air District events in San Francisco County and read about local efforts to improve air quality.

Latest News
  • Jan

    January 12, 2022

    Air District settles case with Air Liquide

    The Air District announced today that Air Liquide Large Industries, US LP, has agreed to pay $159,000 to settle violations that occurred at its hydrogen plant at the San Francisco Oil Refinery in Rodeo.

  • Jan

    January 11, 2022

    First meeting of Air District’s Community Advisory Council to be held January 13

    The Air  District’s Community Advisory Council will hold its first meeting January 13 at 6 PM. In a historic moment, the Air District Board of Directors approved the formation of the Air District’s first Community Advisory Council on November 17, 2021. The Community Advisory Council will advise the Air District’s Board of Directors on environmental justice and equity-based policy and is the first body of its kind at the Bay Area Air District.

  • Jan

    January 5, 2022

    Air District’s Climate Tech Finance program funds acceleration of electric vehicle adoption

    The Air District has awarded a loan guarantee to EvGateway, an electric vehicle solutions management company focused on accelerating the adoption and use of electric vehicles by making them easier to use.

San Francisco County rests at the northern end of the San Francisco Peninsula, bounded by San Mateo County in the south, the Pacific Ocean to the west, San Francisco Bay to the east, and the Golden Gate Bridge to the north. Three San Francisco County representatives sit on the Air District’s Board of Directors.


Because most of San Francisco's landscape is below 200 feet, the marine layer flows across most of the city, creating a cool and windy climate. The southeastern portion of the county, however, tends to be warmer and sunnier, with fewer foggy days. In the winter, average daily temperatures are mild overnight and moderate during the day, while summertime temperatures tend to remain moderate throughout the season. The highest wind speeds are focused along the western coast and generally mild throughout the county. Rainfall averages about 20 inches per year, with the highest amounts reported on the western coast.

San Francisco County's climate is also affected by regional Bay Area climate influences.

Interactive Air Monitoring Stations Map

Air Quality in San Francisco County

Ozone and fine particle pollution, or PM2.5, are the major regional air pollutants of concern in the San Francisco Bay Area. Ozone is primarily a problem in the summer, and fine particle pollution in the winter.

In San Francisco, ozone almost never exceeds health standards and PM2.5 only exceeds the national standard once or twice each year, generally. Being surrounded by water on three sides keeps temperatures within a narrow range, whereby winter low temperatures rarely reach freezing and summer high temperatures stay well below levels where ozone would form and become unhealthy.

Interactive Air Quality Forecast Map

Resource Team

San Francisco County Spare the Air Resource Team promotes ways to reduce air pollution in the local community.

Spare the Air Status

Last Updated: 2/14/2019