Today | Weather | Thursday, March 19, 2026
Active Weather Warnings

Weather in San Francisco, California

03:21 AM
Now
Night
54° F
Feels Like 52°
Precipitation 0 %
Wind 7 mph
Humidity 90 %
Today
Sunny Weather
Day 79°
Night 59°
Precipitation 0 %
Wind 8 mph
UV Index (0 - 11+) 5

San Francisco Weather Forecast Updated

28 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (March 19, 2025)
Cloudy Weather

Day

57°

Night

46°

Wind

7 mph

UV Index

5

Precipitation

25 %

Air Quality in San Francisco

NOW
41 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 4.52 µg/m³
PM10 11.08 µg/m³
O3 0.045 ppm
NO2 0.8 ppb
SO2 0.3 ppb
CO 0.10 ppm
NH3 0 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.54.52 µg/m³
PM1011.08 µg/m³
O387.7 µg/m³
NO21.57 µg/m³
SO20.91 µg/m³
CO117.01 µg/m³
NH30 µg/m³
NO0 µg/m³

Weather Alerts and Warnings for San Francisco

Moderate Expected Likely

Heat Advisory

Heat Advisory issued March 18 at 9:18PM PDT until March 20 at 8:00PM PDT by NWS San Francisco CA
Mar 18, 9:18 PM Mar 20, 8:00 PM
WHAT: High temperatures in the low to mid 90s across the interior
and 80s along the coastline.

WHERE: The Bay Area and Central Coast.

WHEN: Until 8 PM PDT Friday.

IMPACTS: This level of heat affects most individuals sensitive to
heat, especially those without effective cooling and/or adequate
hydration. Impacts possible in some health systems and in
heat-sensitive industries. Hot conditions can cause heat illnesses.

ADDITIONAL DETAILS: Much above normal temperatures in the upper
80s to mid 90s are expected through the remainder of the week
across the Bay Area and Central Coast. Portions of the interior
Central Coast may reach the upper 90s starting mid to late week.
Overnight lows in the upper 50s to low 60s will offer some relief
to the lower elevations but will offer minimal relief within the
higher elevations. Conditions will be much above normal along the
coast this week but coastal residents may experience more relief
overnight than those across the interior. The risk of heat related
illnesses will increase with each additional day of heating from
this event.
+ Read More
Hydration is a critical piece to surviving the heat. Drink water, and if possible, take water to those who are vulnerable. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to the early morning or evening. Take action when you experience symptoms of heat exhaustion and/or heat stroke. Beat the heat and check the backseat! Do not leave young children or pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.
Updated: Mar 19, 2:53 AM Source: NWS Alert