Hourly Weather | Today Wednesday, July 15, 2026
Active Weather Warnings
San Mateo, California
7 PM
Cloudy Weather
77°
Feels Like 73°
0
Humidity: 42%
UV Index: 1
Wind: 20 mph
8 PM
Cloudy Weather
73°
Feels Like 70°
0
Humidity: 46%
UV Index: 0
Wind: 13 mph
9 PM
Cloudy Night
68°
Feels Like 64°
0
Humidity: 58%
UV Index: 0
Wind: 13 mph
10 PM
Cloudy Night
64°
Feels Like 61°
0
Humidity: 66%
UV Index: 0
Wind: 12 mph
11 PM
Cloudy Night
61°
Feels Like 57°
0
Humidity: 76%
UV Index: 0
Wind: 10 mph

Hourly Air Quality Forecast - AQI (US EPA)

7 PM
36 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.74 µg/m³
  • PM10: 19.7 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.2 ppb
  • SO2: 0.4 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

8 PM
35 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.72 µg/m³
  • PM10: 19.8 µg/m³
  • O3: 0.038 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

9 PM
35 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.61 µg/m³
  • PM10: 19.58 µg/m³
  • O3: 0.038 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

10 PM
34 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.45 µg/m³
  • PM10: 19.1 µg/m³
  • O3: 0.037 ppm
  • NO2: 0.4 ppb
  • SO2: 0.4 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

11 PM
34 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.29 µg/m³
  • PM10: 18.59 µg/m³
  • O3: 0.036 ppm
  • NO2: 0.4 ppb
  • SO2: 0.4 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

Weather Alerts and Warnings for San Mateo

Minor Expected Likely

Coastal Flood Advisory

Coastal Flood Advisory issued July 15 at 3:38AM PDT until July 16 at 4:00AM PDT by NWS San Francisco CA
Jul 15, 3:38 AM Jul 16, 4:00 AM
WHAT: Up to 1.5 ft of inundation above ground level is
possible in low-lying areas near shorelines and tidal waterways.

WHERE: Bayshore locations along the San Francisco and San
Pablo Bays.

WHEN: Until 4 AM PDT Thursday.

IMPACTS: Flooding of lots, parks, and roads with only
isolated road closures expected.

ADDITIONAL DETAILS: At the San Francisco tidal gauge, high tide
is expected to be 1.5 ft above normal (7.3 ft MLLW) at 12:48 AM
7/16. These predictions include both astronomical tides and
roughly 3-6 inches of additional water mainly from a combination
of thermal expansion and accumulated sea level rise since the
tidal datum was established (1983-2001). High tide varies up to
90 minutes earlier or later along the Pacific Coast and through
the San Francisco Bay, respectively.
+ Read More
If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property.
Updated: Jul 15, 6:08 PM Source: NWS Alert