Hourly Weather | Today Sunday, May 10, 2026
San Mateo, California
5 AM
Cloudy Night
54°
Feels Like 50°
0
Humidity: 95%
UV Index: 0
Wind: 8 mph
6 AM
Cloudy Night
54°
Feels Like 50°
0
Humidity: 91%
UV Index: 0
Wind: 8 mph
7 AM
Cloudy Weather
54°
Feels Like 52°
0
Humidity: 89%
UV Index: 0
Wind: 8 mph
8 AM
Cloudy Weather
55°
Feels Like 54°
0
Humidity: 83%
UV Index: 1
Wind: 8 mph
9 AM
Cloudy Weather
57°
Feels Like 55°
0
Humidity: 81%
UV Index: 1
Wind: 9 mph
10 AM
Cloudy Weather
61°
Feels Like 59°
0
Humidity: 77%
UV Index: 2
Wind: 9 mph
11 AM
Cloudy Weather
61°
Feels Like 63°
0
Humidity: 74%
UV Index: 3
Wind: 9 mph
12 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 70%
UV Index: 4
Wind: 10 mph
1 PM
Cloudy Weather
64°
Feels Like 66°
0
Humidity: 66%
UV Index: 4
Wind: 10 mph
2 PM
Cloudy Weather
66°
Feels Like 72°
0
Humidity: 63%
UV Index: 9
Wind: 12 mph
3 PM
Cloudy Weather
68°
Feels Like 72°
0
Humidity: 61%
UV Index: 7
Wind: 12 mph
4 PM
Cloudy Weather
66°
Feels Like 68°
0
Humidity: 62%
UV Index: 5
Wind: 13 mph
5 PM
Cloudy Weather
66°
Feels Like 66°
0
Humidity: 62%
UV Index: 3
Wind: 13 mph
6 PM
Cloudy Weather
64°
Feels Like 63°
0
Humidity: 65%
UV Index: 2
Wind: 12 mph
7 PM
Cloudy Weather
63°
Feels Like 61°
0
Humidity: 69%
UV Index: 1
Wind: 12 mph
8 PM
Cloudy Weather
61°
Feels Like 55°
0
Humidity: 75%
UV Index: 0
Wind: 10 mph
9 PM
Cloudy Night
57°
Feels Like 54°
0
Humidity: 81%
UV Index: 0
Wind: 9 mph
10 PM
Cloudy Night
55°
Feels Like 54°
0
Humidity: 83%
UV Index: 0
Wind: 8 mph
11 PM
Cloudy Night
55°
Feels Like 54°
0
Humidity: 84%
UV Index: 0
Wind: 7 mph

Hourly Air Quality Forecast - AQI (US EPA)

5 AM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.62 µg/m³
  • PM10: 11.4 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

6 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.46 µg/m³
  • PM10: 10.46 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

7 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.35 µg/m³
  • PM10: 9.94 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

8 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.3 µg/m³
  • PM10: 9.79 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

9 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.35 µg/m³
  • PM10: 10.56 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

10 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.48 µg/m³
  • PM10: 11.64 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

11 AM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.58 µg/m³
  • PM10: 12.32 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

12 PM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.67 µg/m³
  • PM10: 12.94 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.82 µg/m³
  • PM10: 13.76 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.01 µg/m³
  • PM10: 14.68 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.16 µg/m³
  • PM10: 15.38 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.23 µg/m³
  • PM10: 15.62 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.26 µg/m³
  • PM10: 15.58 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.24 µg/m³
  • PM10: 15.3 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.31 µg/m³
  • PM10: 15.52 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.44 µg/m³
  • PM10: 16.16 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.63 µg/m³
  • PM10: 17.1 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.78 µg/m³
  • PM10: 17.68 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.81 µg/m³
  • PM10: 17.65 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.12 ppm

Health Recommendations:

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