Hourly Weather | Today Saturday, September 19, 2026
Costa Mesa, California
3 AM
Cloudy Night
64°
Feels Like 64°
0
Humidity: 89%
UV Index: 0
Wind: 5 mph
4 AM
Cloudy Night
64°
Feels Like 64°
0
Humidity: 93%
UV Index: 0
Wind: 5 mph
5 AM
Cloudy Night
64°
Feels Like 64°
0
Humidity: 93%
UV Index: 0
Wind: 5 mph
6 AM
Cloudy Night
63°
Feels Like 64°
0
Humidity: 94%
UV Index: 0
Wind: 4 mph
7 AM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 95%
UV Index: 0
Wind: 4 mph
8 AM
Cloudy Weather
66°
Feels Like 68°
0
Humidity: 81%
UV Index: 1
Wind: 4 mph
9 AM
Cloudy Weather
70°
Feels Like 73°
0
Humidity: 81%
UV Index: 2
Wind: 5 mph
10 AM
Cloudy Weather
72°
Feels Like 75°
0
Humidity: 76%
UV Index: 3
Wind: 5 mph
11 AM
Cloudy Weather
73°
Feels Like 79°
0
Humidity: 72%
UV Index: 5
Wind: 6 mph
12 PM
Cloudy Weather
75°
Feels Like 82°
0
Humidity: 68%
UV Index: 6
Wind: 7 mph
1 PM
Cloudy Weather
75°
Feels Like 82°
0
Humidity: 65%
UV Index: 7
Wind: 8 mph
2 PM
Cloudy Weather
77°
Feels Like 82°
0
Humidity: 63%
UV Index: 6
Wind: 8 mph
3 PM
Cloudy Weather
79°
Feels Like 82°
0
Humidity: 61%
UV Index: 5
Wind: 8 mph
4 PM
Cloudy Weather
77°
Feels Like 79°
0
Humidity: 63%
UV Index: 3
Wind: 8 mph
5 PM
Cloudy Weather
75°
Feels Like 77°
0
Humidity: 66%
UV Index: 2
Wind: 8 mph
6 PM
Cloudy Weather
75°
Feels Like 75°
0
Humidity: 69%
UV Index: 1
Wind: 7 mph
7 PM
Cloudy Night
72°
Feels Like 72°
0
Humidity: 76%
UV Index: 0
Wind: 6 mph
8 PM
Cloudy Night
72°
Feels Like 72°
0
Humidity: 79%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Night
70°
Feels Like 70°
0
Humidity: 82%
UV Index: 0
Wind: 5 mph
10 PM
Cloudy Night
70°
Feels Like 70°
0
Humidity: 84%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
68°
Feels Like 68°
0
Humidity: 86%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

3 AM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 7.87 µg/m³
  • PM10: 24.71 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

4 AM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 7.75 µg/m³
  • PM10: 24.45 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.69 µg/m³
  • PM10: 24.48 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.68 µg/m³
  • PM10: 24.58 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.68 µg/m³
  • PM10: 24.57 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.71 µg/m³
  • PM10: 24.54 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.77 µg/m³
  • PM10: 24.22 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.91 µg/m³
  • PM10: 23.95 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 8.15 µg/m³
  • PM10: 23.95 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 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: 8.46 µg/m³
  • PM10: 24.18 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 8.82 µg/m³
  • PM10: 24.59 µg/m³
  • O3: 0.050 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 9.24 µg/m³
  • PM10: 25.11 µg/m³
  • O3: 0.051 ppm
  • NO2: 0.1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 9.71 µg/m³
  • PM10: 25.95 µg/m³
  • O3: 0.052 ppm
  • NO2: 0.1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 10.12 µg/m³
  • PM10: 27.25 µg/m³
  • O3: 0.052 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 10.32 µg/m³
  • PM10: 28.36 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 10.28 µg/m³
  • PM10: 29.1 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 10.02 µg/m³
  • PM10: 29.75 µg/m³
  • O3: 0.052 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 9.61 µg/m³
  • PM10: 30.32 µg/m³
  • O3: 0.051 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.

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

Pollutant Concentrations:

  • PM2.5: 9.17 µg/m³
  • PM10: 30.6 µg/m³
  • O3: 0.051 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
46 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 8.75 µg/m³
  • PM10: 30.43 µg/m³
  • O3: 0.050 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
46 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 8.37 µg/m³
  • PM10: 30.07 µg/m³
  • O3: 0.050 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.