Hourly Weather Forecast for El Cajon, California

Hourly Weather | Today › Wednesday, March 18, 2026

Active Weather Warnings

Extreme Heat Watch
Heat Advisory

El Cajon, California

7 AM

63°

Feels Like 63°

Humidity: 51%

UV Index: 0

Wind: 4 mph

8 AM

68°

Feels Like 68°

Humidity: 49%

UV Index: 1

Wind: 4 mph

9 AM

73°

Feels Like 75°

Humidity: 39%

UV Index: 2

Wind: 4 mph

10 AM

81°

Feels Like 84°

Humidity: 31%

UV Index: 3

Wind: 5 mph

11 AM

88°

Feels Like 91°

Humidity: 26%

UV Index: 5

Wind: 6 mph

12 PM

91°

Feels Like 95°

Humidity: 24%

UV Index: 6

Wind: 7 mph

1 PM

93°

Feels Like 97°

Humidity: 23%

UV Index: 7

Wind: 8 mph

2 PM

93°

Feels Like 97°

Humidity: 23%

UV Index: 6

Wind: 9 mph

3 PM

91°

Feels Like 93°

Humidity: 25%

UV Index: 5

Wind: 9 mph

4 PM

90°

Feels Like 91°

Humidity: 27%

UV Index: 3

Wind: 8 mph

5 PM

88°

Feels Like 88°

Humidity: 30%

UV Index: 2

Wind: 8 mph

6 PM

84°

Feels Like 82°

Humidity: 33%

UV Index: 1

Wind: 7 mph

7 PM

79°

Feels Like 77°

Humidity: 41%

UV Index: 0

Wind: 6 mph

8 PM

75°

Feels Like 73°

Humidity: 47%

UV Index: 0

Wind: 5 mph

9 PM

72°

Feels Like 70°

Humidity: 54%

UV Index: 0

Wind: 5 mph

10 PM

70°

Feels Like 66°

Humidity: 61%

UV Index: 0

Wind: 5 mph

11 PM

66°

Feels Like 64°

Humidity: 67%

UV Index: 0

Wind: 4 mph

Hourly Air Quality Forecast - AQI (US EPA)

7 AM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.58 µg/m³
PM₁₀: 36.55 µg/m³
O₃: 0.036 ppm
NO₂: 0.7 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

8 AM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.51 µg/m³
PM₁₀: 36.47 µg/m³
O₃: 0.035 ppm
NO₂: 0.8 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

9 AM

78 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.3 µg/m³
PM₁₀: 35.99 µg/m³
O₃: 0.034 ppm
NO₂: 0.7 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

10 AM

78 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.33 µg/m³
PM₁₀: 35.95 µg/m³
O₃: 0.035 ppm
NO₂: 0.6 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

11 AM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.38 µg/m³
PM₁₀: 36.14 µg/m³
O₃: 0.037 ppm
NO₂: 0.5 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

12 PM

78 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.11 µg/m³
PM₁₀: 36.03 µg/m³
O₃: 0.040 ppm
NO₂: 0.3 ppb
SO₂: 0.2 ppb
CO: 0.16 ppm

Health Recommendations:

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

1 PM

78 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 24.95 µg/m³
PM₁₀: 36.07 µg/m³
O₃: 0.042 ppm
NO₂: 0.2 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

2 PM

78 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.11 µg/m³
PM₁₀: 36.42 µg/m³
O₃: 0.043 ppm
NO₂: 0.2 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

3 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.41 µg/m³
PM₁₀: 36.97 µg/m³
O₃: 0.045 ppm
NO₂: 0.2 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

4 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.5 µg/m³
PM₁₀: 37.12 µg/m³
O₃: 0.046 ppm
NO₂: 0.2 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

5 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.59 µg/m³
PM₁₀: 37.18 µg/m³
O₃: 0.047 ppm
NO₂: 0.3 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

6 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.72 µg/m³
PM₁₀: 37.01 µg/m³
O₃: 0.047 ppm
NO₂: 0.4 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

7 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.77 µg/m³
PM₁₀: 36.68 µg/m³
O₃: 0.046 ppm
NO₂: 0.6 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

8 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.77 µg/m³
PM₁₀: 36.42 µg/m³
O₃: 0.046 ppm
NO₂: 0.6 ppb
SO₂: 0.2 ppb
CO: 0.15 ppm

Health Recommendations:

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

9 PM

80 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.88 µg/m³
PM₁₀: 36.31 µg/m³
O₃: 0.045 ppm
NO₂: 0.7 ppb
SO₂: 0.3 ppb
CO: 0.15 ppm

Health Recommendations:

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

10 PM

80 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.88 µg/m³
PM₁₀: 36.14 µg/m³
O₃: 0.044 ppm
NO₂: 0.7 ppb
SO₂: 0.3 ppb
CO: 0.15 ppm

Health Recommendations:

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

11 PM

79 AQI

Moderate air quality Dominant pollutant: PM_2.5

Details

Pollutant Concentrations:

PM_2.5: 25.4 µg/m³
PM₁₀: 35.55 µg/m³
O₃: 0.043 ppm
NO₂: 0.7 ppb
SO₂: 0.2 ppb
CO: 0.15 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 El Cajon

Severe Future Likely

Extreme Heat Watch

Extreme Heat Watch issued March 14 at 5:51AM PDT until March 20 at 8:00PM PDT by NWS San Diego CA

Mar 16, 10:00 AM → Mar 20, 8:00 PM

WHAT: Dangerously hot conditions with temperatures 85 to 90 near
the coast, up to 105 inland.

WHERE: Orange County Coastal Areas, Orange County Inland Areas,
San Bernardino and Riverside County Valleys-The Inland Empire, San
Diego County Coastal Areas, San Diego County Valleys, and Santa
Ana Mountains and Foothills.

WHEN: From Monday morning through Friday evening.

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

ADDITIONAL DETAILS: High temperatures next week will be 20 to
potentially 30 degrees above
normal for this time of year, where record breaking heat is likely.

+ Read More

Updated: Mar 14, 12:14 PM Source: NWS Alert

Moderate Expected Likely

Heat Advisory

Heat Advisory issued March 18 at 2:49AM PDT until March 20 at 8:00PM PDT by NWS San Diego CA

Mar 18, 2:49 AM → Mar 20, 8:00 PM

WHAT: High temperatures in the upper 90s to 104 expected.

WHERE: San Diego County Valleys.

WHEN: Until 8 PM PDT Friday.

IMPACTS: Hot temperatures may cause heat illnesses.

+ 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. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.

Updated: Mar 18, 6:10 AM Source: NWS Alert

Hourly Air Quality Forecast - AQI (US EPA)

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Pollutant Concentrations:

Health Recommendations:

Weather Alerts and Warnings for El Cajon

Extreme Heat Watch

Heat Advisory

Explore U.S. Weather Trends