Hour-by-hour environmental exposure forecast for San Francisco. Know when to go out and when to stay in.

Air Quality Index 31
Temperature145.2°F
Humidity54.0%
Wind Speed2.5 mph
NOTICE: Safety and air quality are subjective and fluctuate in real-time. This report is a data-driven starting point. Always exercise personal judgment, stay aware of your surroundings, and consult official local law enforcement or health department resources for real-time safety and health advice.
Good 31 AQI · Total Lung Freedom Updated: May 17, 1:29 PM

The inland setting means local environmental conditions are shaped more by urban density than coastal influences.

In line with average conditions across San Francisco

24-Hour AQI Trend

AQI trend chart — current reading: 31 (Total Lung Freedom). May 17, 1:29 PM.

Pollutant Breakdown

PM2.5 6.70 µg/m³ Fine particulate matter — penetrates deep into lungs
PM10 10.20 µg/m³ Coarse particulate matter — dust and pollen
NO₂ 3.50 ppb Nitrogen dioxide — traffic and combustion marker
O₃ 72.00 ppb Ground-level ozone — forms in sunlight from pollutants

Peer Comparison

In line with average conditions across San Francisco

San Francisco
31

Why San Francisco's Air Is What It Is

San Francisco sits in an inland urban setting where local environmental conditions are shaped primarily by density and development patterns. Temperature swings between day and night can be more pronounced than in coastal areas.

Historical Context

Current AQI of 31 reflects recent monitoring data. Local conditions can shift with weather patterns, traffic volume, and seasonal factors.

24-Hour Hourly Forecast

Best window: 05:00 (AQI 31) · Peak AQI: 41 at 21:00

TimeAQITemp (°F)HumidityWind (mph)PM2.5PM10
00:0036129.266%5.79.514.8
01:0035127.670%2.48.813.5
02:0034127.068%3.38.112.5
03:0033126.365%3.07.811.9
04:0032123.670%4.27.812.0
05:0031121.872%4.27.110.9
06:0031121.874%2.56.810.2
07:0031125.275%1.66.39.5
08:0031132.877%0.46.19.4
09:0031136.670%0.16.29.5
10:0031143.257%2.16.710.2
11:0031150.345%3.76.710.1
12:0032153.144%5.66.610.1
13:0032158.240%6.06.710.3
14:0033159.839%7.06.710.4
15:0034161.837%6.86.510.0
16:0036162.535%7.15.88.9
17:0037167.714%10.75.17.7
18:0038167.015%11.25.78.6
19:0039162.117%9.96.08.8
20:0040155.820%8.96.59.7
21:0041152.122%9.45.98.6
22:0041148.324%8.95.57.8
23:0041146.125%9.35.17.1

Air quality is forecast to be good for most of the day. Great time for outdoor activities!

For those in San Francisco who want to make the most of outdoor time, the forecast points to 05:00 (AQI 31) as the ideal window. The AQI drops to 31 at 05:00, while the highest reading of 41 occurs at 21:00 during 21:00 (AQI 41). For those planning outdoor exercise in San Francisco, the forecast offers useful timing information. Air quality is forecast to be good for most of the day. Great time for outdoor activities! Adjusting the intensity and duration of activities based on forecasted conditions is a common approach among fitness enthusiasts.

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Disclaimer: The information provided on this site is for informational purposes only and does not constitute professional advice. Air quality, safety, and environmental data are subject to change and may not reflect real-time conditions. Always verify with official local sources before making decisions that affect your health or safety.