Hourly Weather | Today Wednesday, November 19, 2025
San Mateo, California
1 PM
Cloudy Weather
61°
Feels Like 61°
3
Humidity: 73%
Wind: 7 mph
UV Index: 1
2 PM
Cloudy Weather
61°
Feels Like 61°
3
Humidity: 70%
Wind: 7 mph
UV Index: 1
3 PM
Cloudy Weather
61°
Feels Like 59°
3
Humidity: 74%
Wind: 7 mph
UV Index: 1
4 PM
Cloudy Weather
59°
Feels Like 57°
3
Humidity: 76%
Wind: 7 mph
UV Index: 0
5 PM
Cloudy Weather
57°
Feels Like 55°
3
Humidity: 78%
Wind: 7 mph
UV Index: 0
6 PM
Cloudy Weather
57°
Feels Like 54°
4
Humidity: 80%
Wind: 7 mph
UV Index: 0
7 PM
Cloudy Weather
55°
Feels Like 54°
7
Humidity: 78%
Wind: 7 mph
UV Index: 0
8 PM
Cloudy Weather
55°
Feels Like 54°
7
Humidity: 77%
Wind: 7 mph
UV Index: 0
9 PM
Cloudy Weather
55°
Feels Like 54°
7
Humidity: 78%
Wind: 7 mph
UV Index: 0
10 PM
Cloudy Weather
55°
Feels Like 52°
7
Humidity: 80%
Wind: 7 mph
UV Index: 0
11 PM
Cloudy Weather
55°
Feels Like 52°
7
Humidity: 80%
Wind: 7 mph
UV Index: 0

Hourly Air Quality Forecast - AQI (US EPA)

1 PM
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.74 µg/m³
  • PM10: 9.03 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

2 PM
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.67 µg/m³
  • PM10: 8.93 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

3 PM
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.52 µg/m³
  • PM10: 8.66 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

4 PM
42 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.29 µg/m³
  • PM10: 8.12 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

5 PM
42 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.05 µg/m³
  • PM10: 7.43 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

6 PM
42 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.8 µg/m³
  • PM10: 6.66 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.58 µg/m³
  • PM10: 5.93 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.45 µg/m³
  • PM10: 5.29 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.42 µg/m³
  • PM10: 4.91 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.43 µg/m³
  • PM10: 4.77 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.43 µg/m³
  • PM10: 4.39 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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