Hourly Weather | Today Monday, April 27, 2026
San Marcos, California
4 PM
Cloudy Weather
64°
Feels Like 66°
0
Humidity: 52%
UV Index: 4
Wind: 12 mph
5 PM
Cloudy Weather
64°
Feels Like 64°
0
Humidity: 53%
UV Index: 3
Wind: 10 mph
6 PM
Cloudy Weather
63°
Feels Like 63°
0
Humidity: 55%
UV Index: 2
Wind: 9 mph
7 PM
Cloudy Weather
61°
Feels Like 57°
0
Humidity: 62%
UV Index: 1
Wind: 8 mph
8 PM
Cloudy Night
61°
Feels Like 57°
0
Humidity: 63%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Night
57°
Feels Like 55°
0
Humidity: 70%
UV Index: 0
Wind: 6 mph
10 PM
Cloudy Night
54°
Feels Like 54°
0
Humidity: 76%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
52°
Feels Like 52°
0
Humidity: 81%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

4 PM
58 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.83 µg/m³
  • PM10: 1.81 µg/m³
  • O3: 0.056 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

5 PM
60 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.9 µg/m³
  • PM10: 1.91 µg/m³
  • O3: 0.057 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

6 PM
64 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.97 µg/m³
  • PM10: 2.03 µg/m³
  • O3: 0.059 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

7 PM
68 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.06 µg/m³
  • PM10: 2.27 µg/m³
  • O3: 0.060 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

8 PM
71 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.16 µg/m³
  • PM10: 2.58 µg/m³
  • O3: 0.061 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

9 PM
74 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.24 µg/m³
  • PM10: 2.9 µg/m³
  • O3: 0.062 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

10 PM
77 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.32 µg/m³
  • PM10: 3.25 µg/m³
  • O3: 0.063 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

11 PM
80 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.4 µg/m³
  • PM10: 3.65 µg/m³
  • O3: 0.063 ppm
  • NO2: 0.1 ppb
  • SO2: 0.2 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.