Weather factors to check
- Winter atmospheric river storms with heavy rain and wind
- Wildfire smoke drifting in from inland fires in late summer
Air Quality
San Francisco Air Quality App
Air quality is part of everyday weather planning, especially for workouts, commuting, wildfire smoke, heat, and sensitive groups. A local forecast should make that context easy to act on in San Francisco.
Local Air Quality Answer
Quick answer for San Francisco air quality
Air quality planning in San Francisco works best when weather context is included, because heat, humidity, wind, smoke, dust, and stagnant air can change outdoor risk quickly.
When conditions can shift
San Francisco's key windows are the summer fog season, winter atmospheric river storms, and late-summer or fall smoke events from regional wildfires.
Best planning uses
- Comparing foggy and sunny neighborhoods
- Timing winter storms and atmospheric rivers
- Monitoring wildfire smoke and air quality
- Planning around the city's sharp microclimates
Air quality changes how weather feels
For San Francisco, temperature, humidity, wind, and air quality together determine whether outdoor plans feel comfortable or risky.
Plan before you head outside
WeatherAI helps connect air quality with forecast timing so you can adjust workouts, commutes, errands, and travel plans around San Francisco.
Local Weather Context for San Francisco
San Francisco has a cool Mediterranean climate with dry summers and wet winters. At the downtown San Francisco station, the 1991-2020 reference averages range from a daily high of 58°F (14°C) in Jan to 70°F (21°C) in Sep. Monthly precipitation averages sum to 22.9 inches (581 mm) per year.
Summer fog and ocean air often keep coastal neighborhoods cool while inland areas are much warmer. September has the highest average daily maximum in the station climate table. Most rain falls in the cooler months, and neighborhood temperatures vary with marine-layer coverage and wind.
Local Planning Guide
How to Plan Around San Francisco Weather
San Francisco's key windows are the summer fog season, winter atmospheric river storms, and late-summer or fall smoke events from regional wildfires.
Local Hazards to Watch
- Dense summer fog that keeps coastal neighborhoods cold and gray
- Extreme microclimate temperature swings across the city
- Winter atmospheric river storms with heavy rain and wind
- Wildfire smoke drifting in from inland fires in late summer
Best WeatherAI Uses Here
- Comparing foggy and sunny neighborhoods
- Timing winter storms and atmospheric rivers
- Monitoring wildfire smoke and air quality
- Planning around the city's sharp microclimates
Radar and Alert Context
Weather radar helps track rain, but shallow fog may not appear on precipitation radar. Pair rain imagery with visibility observations, satellite imagery, and local forecasts when comparing coastal and inland neighborhoods.
More San Francisco Weather Pages
Related local weather pages for nearby forecasts, radar, alerts, and conditions.
Local Weather Radar
San Francisco Weather Radar: Local Guide to Reading Storms
How to read San Francisco weather radar: storm motion, precipitation type, and what to check before rain reaches your neighborhood.
Local Storm Tracker
San Francisco Storm Tracker App
Track storms near San Francisco with radar loops, storm movement, local alerts, saved places, and WeatherAI storm tracking features for iPhone, iPad, Mac, and Vision Pro.
Local Alerts
San Francisco Weather Alerts App
Get local weather alert guidance for San Francisco, including severe weather, wind, rain, heat, and daily planning notifications in WeatherAI.
Useful Guides and Tools
Use these resources to interpret local conditions and plan around changing weather.
Tool
AQI Exposure Planner
Plan outdoor activity around AQI, wildfire smoke, sensitive groups, and exertion.
Tool
Wind Chill Calculator
Estimate cold-weather exposure risk from temperature and wind speed.
Guide
How to Read Weather Radar
Learn the basics of radar interpretation so you can tell where storms are headed and how intense they may become.
Glossary
Visibility
The horizontal distance at which objects can be seen and identified.
Bring San Francisco Weather Into the App
WeatherAI gives you local forecasts, radar, alerts, air quality, and conversational weather answers for iPhone, iPad, Mac, and Vision Pro.