Hourly Weather | Today Tuesday, July 21, 2026
San Marcos, California
2 AM
Cloudy Night
66°
Feels Like 66°
7
Humidity: 83%
UV Index: 0
Wind: 5 mph
3 AM
Cloudy Night
66°
Feels Like 64°
7
Humidity: 84%
UV Index: 0
Wind: 4 mph
4 AM
Cloudy Night
66°
Feels Like 64°
7
Humidity: 85%
UV Index: 0
Wind: 4 mph
5 AM
Cloudy Night
64°
Feels Like 64°
7
Humidity: 86%
UV Index: 0
Wind: 4 mph
6 AM
Cloudy Weather
66°
Feels Like 66°
7
Humidity: 79%
UV Index: 0
Wind: 4 mph
7 AM
Cloudy Weather
70°
Feels Like 72°
5
Humidity: 70%
UV Index: 1
Wind: 4 mph
8 AM
Cloudy Weather
72°
Feels Like 72°
0
Humidity: 68%
UV Index: 0
Wind: 5 mph
9 AM
Cloudy Weather
75°
Feels Like 77°
0
Humidity: 57%
UV Index: 2
Wind: 6 mph
10 AM
Cloudy Weather
81°
Feels Like 84°
0
Humidity: 52%
UV Index: 5
Wind: 7 mph
11 AM
Cloudy Weather
82°
Feels Like 90°
0
Humidity: 48%
UV Index: 8
Wind: 8 mph
12 PM
Cloudy Weather
84°
Feels Like 91°
0
Humidity: 45%
UV Index: 11
Wind: 8 mph
1 PM
Cloudy Weather
84°
Feels Like 91°
0
Humidity: 42%
UV Index: 11
Wind: 9 mph
2 PM
Cloudy Weather
86°
Feels Like 91°
0
Humidity: 39%
UV Index: 11
Wind: 10 mph
3 PM
Sunny Weather
84°
Feels Like 90°
0
Humidity: 40%
UV Index: 8
Wind: 10 mph
4 PM
Sunny Weather
84°
Feels Like 86°
0
Humidity: 41%
UV Index: 5
Wind: 10 mph
5 PM
Sunny Weather
82°
Feels Like 84°
0
Humidity: 43%
UV Index: 3
Wind: 9 mph
6 PM
Cloudy Weather
81°
Feels Like 81°
0
Humidity: 46%
UV Index: 2
Wind: 8 mph
7 PM
Cloudy Weather
79°
Feels Like 77°
0
Humidity: 52%
UV Index: 1
Wind: 7 mph
8 PM
Cloudy Night
75°
Feels Like 73°
0
Humidity: 61%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Night
73°
Feels Like 72°
0
Humidity: 68%
UV Index: 0
Wind: 5 mph
10 PM
Cloudy Night
70°
Feels Like 68°
0
Humidity: 75%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
66°
Feels Like 66°
0
Humidity: 81%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

2 AM
33 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.82 µg/m³
  • PM10: 14.68 µg/m³
  • O3: 0.035 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.88 µg/m³
  • PM10: 14.62 µg/m³
  • O3: 0.035 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.98 µg/m³
  • PM10: 14.69 µg/m³
  • O3: 0.034 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.08 µg/m³
  • PM10: 14.76 µg/m³
  • O3: 0.034 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.16 µg/m³
  • PM10: 14.78 µg/m³
  • O3: 0.033 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.19 µg/m³
  • PM10: 14.69 µg/m³
  • O3: 0.033 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.18 µg/m³
  • PM10: 14.42 µg/m³
  • O3: 0.033 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.11 µg/m³
  • PM10: 13.96 µg/m³
  • O3: 0.034 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.03 µg/m³
  • PM10: 13.58 µg/m³
  • O3: 0.035 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.9 µg/m³
  • PM10: 13.15 µg/m³
  • O3: 0.036 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.7 µg/m³
  • PM10: 12.55 µg/m³
  • O3: 0.037 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.43 µg/m³
  • PM10: 11.91 µg/m³
  • O3: 0.038 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.13 µg/m³
  • PM10: 11.28 µg/m³
  • O3: 0.038 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.8 µg/m³
  • PM10: 10.64 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.54 µg/m³
  • PM10: 10.18 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.32 µg/m³
  • PM10: 9.85 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.15 µg/m³
  • PM10: 9.63 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.02 µg/m³
  • PM10: 9.5 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.98 µg/m³
  • PM10: 9.55 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.04 µg/m³
  • PM10: 9.77 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.11 µg/m³
  • PM10: 9.95 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.14 µg/m³
  • PM10: 10.03 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.07 ppm

Health Recommendations:

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