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Today Hourly 7 days 30 days Air Quality
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Hourly Weather | Today › Saturday, August 29, 2026
Active Weather Warnings
San Marcos, California
3 AM
Cloudy Night
72°
Feels Like 73°
0
Humidity: 95%
UV Index: 0
Wind: 4 mph
4 AM
Cloudy Night
70°
Feels Like 72°
0
Humidity: 88%
UV Index: 0
Wind: 4 mph
5 AM
Cloudy Weather
70°
Feels Like 70°
0
Humidity: 90%
UV Index: 0
Wind: 4 mph
6 AM
Cloudy Weather
68°
Feels Like 70°
0
Humidity: 92%
UV Index: 0
Wind: 4 mph
7 AM
Cloudy Weather
72°
Feels Like 72°
0
Humidity: 82%
UV Index: 0
Wind: 4 mph
8 AM
Cloudy Weather
75°
Feels Like 81°
0
Humidity: 73%
UV Index: 2
Wind: 4 mph
9 AM
Cloudy Weather
81°
Feels Like 86°
0
Humidity: 63%
UV Index: 3
Wind: 6 mph
10 AM
Cloudy Weather
86°
Feels Like 91°
0
Humidity: 54%
UV Index: 4
Wind: 7 mph
11 AM
Sunny Weather
90°
Feels Like 97°
0
Humidity: 48%
UV Index: 6
Wind: 8 mph
12 PM
Sunny Weather
91°
Feels Like 99°
0
Humidity: 46%
UV Index: 8
Wind: 9 mph
1 PM
Sunny Weather
93°
Feels Like 100°
0
Humidity: 44%
UV Index: 9
Wind: 9 mph
2 PM
Sunny Weather
91°
Feels Like 99°
0
Humidity: 45%
UV Index: 8
Wind: 10 mph
3 PM
Sunny Weather
91°
Feels Like 97°
0
Humidity: 46%
UV Index: 6
Wind: 10 mph
4 PM
Sunny Weather
90°
Feels Like 93°
0
Humidity: 47%
UV Index: 4
Wind: 9 mph
5 PM
Sunny Weather
88°
Feels Like 90°
0
Humidity: 51%
UV Index: 3
Wind: 9 mph
6 PM
Cloudy Weather
84°
Feels Like 88°
0
Humidity: 56%
UV Index: 2
Wind: 8 mph
7 PM
Cloudy Weather
82°
Feels Like 84°
0
Humidity: 65%
UV Index: 0
Wind: 6 mph
8 PM
Cloudy Night
79°
Feels Like 82°
0
Humidity: 74%
UV Index: 0
Wind: 5 mph
9 PM
Cloudy Night
75°
Feels Like 79°
0
Humidity: 78%
UV Index: 0
Wind: 5 mph
10 PM
Cloudy Night
73°
Feels Like 77°
0
Humidity: 84%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
72°
Feels Like 75°
0
Humidity: 88%
UV Index: 0
Wind: 4 mph

Hourly Air Quality Forecast - AQI (US EPA)

3 AM
90 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 30.85 µg/m³
  • PM10: 45.66 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

4 AM
89 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 30.14 µg/m³
  • PM10: 45.39 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

5 AM
94 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 32.63 µg/m³
  • PM10: 48.52 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

6 AM
107 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 38.02 µg/m³
  • PM10: 54.53 µg/m³
  • O3: 0.044 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.14 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

7 AM
123 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 44.74 µg/m³
  • PM10: 61.88 µg/m³
  • O3: 0.043 ppm
  • NO2: 0.6 ppb
  • SO2: 0.2 ppb
  • CO: 0.14 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

8 AM
140 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 51.24 µg/m³
  • PM10: 69.08 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.6 ppb
  • SO2: 0.2 ppb
  • CO: 0.15 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

9 AM
150 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 55.74 µg/m³
  • PM10: 74.18 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.6 ppb
  • SO2: 0.2 ppb
  • CO: 0.16 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

10 AM
152 AQI
Unhealthy air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 58.43 µg/m³
  • PM10: 77.69 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.16 ppm

Health Recommendations:

Everyone may begin to experience health effects; sensitive groups may experience more serious effects.

11 AM
152 AQI
Unhealthy air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 58.42 µg/m³
  • PM10: 78.6 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.16 ppm

Health Recommendations:

Everyone may begin to experience health effects; sensitive groups may experience more serious effects.

12 PM
147 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 54.18 µg/m³
  • PM10: 75.09 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.15 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

1 PM
128 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 46.7 µg/m³
  • PM10: 68.39 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.14 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

2 PM
106 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 37.94 µg/m³
  • PM10: 60.37 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.12 ppm

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is less likely to be affected.

3 PM
87 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 29.54 µg/m³
  • PM10: 52.64 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.2 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.

4 PM
75 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 23.55 µg/m³
  • PM10: 47.16 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

5 PM
67 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 19.92 µg/m³
  • PM10: 44.02 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

6 PM
62 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 17.81 µg/m³
  • PM10: 41.99 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

7 PM
60 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 16.6 µg/m³
  • PM10: 40.48 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

8 PM
58 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 15.64 µg/m³
  • PM10: 39.02 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

9 PM
56 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 14.75 µg/m³
  • PM10: 37.47 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

10 PM
53 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 13.56 µg/m³
  • PM10: 36.21 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

11 PM
51 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 12.38 µg/m³
  • PM10: 35.3 µg/m³
  • O3: 0.042 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

Current Real-Time Air Quality Report

Weather Alerts and Warnings for San Marcos

Severe Expected Likely

Extreme Heat Warning

Extreme Heat Warning issued August 28 at 9:06PM PDT until August 29 at 8:00PM PDT by NWS San Diego CA
Aug 28, 9:06 PM → Aug 29, 8:00 PM
WHAT: Hot conditions continue into Saturday with high temperatures
up to 98 degrees. Lows will be in the low 70s.

WHERE: San Diego County Valleys.

WHEN: Until 8 PM PDT Saturday.

IMPACTS: Heat related illnesses increase significantly during
extreme heat events.

ADDITIONAL DETAILS: Temperatures will fall to below normal by
Sunday.
+ Read More
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.
Updated: Aug 29, 1:21 AM Source: NWS Alert

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