Hourly Weather Forecast for Philadelphia, Pennsylvania

Hourly Weather | Today › Wednesday, May 20, 2026

Active Weather Warnings

Heat Advisory

Philadelphia, Pennsylvania

1 AM

70°

Feels Like 66°

Humidity: 67%

UV Index: 0

Wind: 8 mph

2 AM

66°

Feels Like 61°

Humidity: 67%

UV Index: 0

Wind: 7 mph

3 AM

64°

Feels Like 63°

Humidity: 61%

UV Index: 0

Wind: 8 mph

4 AM

63°

Feels Like 61°

Humidity: 57%

UV Index: 0

Wind: 9 mph

5 AM

63°

Feels Like 59°

Humidity: 53%

UV Index: 0

Wind: 9 mph

6 AM

61°

Feels Like 57°

Humidity: 53%

UV Index: 0

Wind: 9 mph

7 AM

61°

Feels Like 57°

Humidity: 54%

UV Index: 0

Wind: 9 mph

8 AM

61°

Feels Like 59°

Humidity: 53%

UV Index: 1

Wind: 8 mph

9 AM

61°

Feels Like 61°

Humidity: 55%

UV Index: 1

Wind: 8 mph

10 AM

61°

Feels Like 61°

Humidity: 60%

UV Index: 1

Wind: 8 mph

11 AM

61°

Feels Like 57°

Humidity: 64%

UV Index: 2

Wind: 8 mph

12 PM

63°

Feels Like 64°

Humidity: 63%

UV Index: 3

Wind: 8 mph

1 PM

63°

Feels Like 63°

Humidity: 60%

UV Index: 3

Wind: 8 mph

2 PM

63°

Feels Like 61°

Humidity: 66%

UV Index: 2

Wind: 7 mph

3 PM

64°

Feels Like 66°

Humidity: 59%

UV Index: 2

Wind: 7 mph

4 PM

63°

Feels Like 61°

Humidity: 68%

UV Index: 1

Wind: 7 mph

5 PM

64°

Feels Like 64°

Humidity: 62%

UV Index: 1

Wind: 6 mph

6 PM

63°

Feels Like 63°

Humidity: 61%

UV Index: 1

Wind: 6 mph

7 PM

63°

Feels Like 63°

Humidity: 61%

UV Index: 0

Wind: 6 mph

8 PM

63°

Feels Like 61°

Humidity: 61%

UV Index: 0

Wind: 5 mph

9 PM

61°

Feels Like 61°

Humidity: 65%

UV Index: 0

Wind: 4 mph

10 PM

59°

Feels Like 59°

Humidity: 68%

UV Index: 0

Wind: 4 mph

11 PM

59°

Feels Like 59°

Humidity: 69%

UV Index: 0

Wind: 4 mph

Hourly Air Quality Forecast - AQI (US EPA)

1 AM

40 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.9 µg/m³
PM₁₀: 9.29 µg/m³
O₃: 0.043 ppm
NO₂: 1.4 ppb
SO₂: 0.5 ppb
CO: 0.11 ppm

Health Recommendations:

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

2 AM

38 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.52 µg/m³
PM₁₀: 8.82 µg/m³
O₃: 0.041 ppm
NO₂: 1.3 ppb
SO₂: 0.5 ppb
CO: 0.11 ppm

Health Recommendations:

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

3 AM

37 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.25 µg/m³
PM₁₀: 8.5 µg/m³
O₃: 0.040 ppm
NO₂: 1.3 ppb
SO₂: 0.5 ppb
CO: 0.11 ppm

Health Recommendations:

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

4 AM

36 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.14 µg/m³
PM₁₀: 8.42 µg/m³
O₃: 0.039 ppm
NO₂: 1.3 ppb
SO₂: 0.5 ppb
CO: 0.11 ppm

Health Recommendations:

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

5 AM

35 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.11 µg/m³
PM₁₀: 8.45 µg/m³
O₃: 0.037 ppm
NO₂: 1.4 ppb
SO₂: 0.5 ppb
CO: 0.11 ppm

Health Recommendations:

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

6 AM

33 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.07 µg/m³
PM₁₀: 8.5 µg/m³
O₃: 0.036 ppm
NO₂: 1.5 ppb
SO₂: 0.6 ppb
CO: 0.11 ppm

Health Recommendations:

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

7 AM

31 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.08 µg/m³
PM₁₀: 8.64 µg/m³
O₃: 0.034 ppm
NO₂: 1.7 ppb
SO₂: 0.6 ppb
CO: 0.11 ppm

Health Recommendations:

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

8 AM

30 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.16 µg/m³
PM₁₀: 8.87 µg/m³
O₃: 0.033 ppm
NO₂: 1.8 ppb
SO₂: 0.6 ppb
CO: 0.11 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:

PM_2.5: 5.35 µg/m³
PM₁₀: 9.21 µg/m³
O₃: 0.033 ppm
NO₂: 1.7 ppb
SO₂: 0.7 ppb
CO: 0.12 ppm

Health Recommendations:

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

10 AM

34 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.84 µg/m³
PM₁₀: 9.77 µg/m³
O₃: 0.036 ppm
NO₂: 1.6 ppb
SO₂: 0.8 ppb
CO: 0.12 ppm

Health Recommendations:

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

11 AM

39 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 7.07 µg/m³
PM₁₀: 10.94 µg/m³
O₃: 0.042 ppm
NO₂: 1.3 ppb
SO₂: 1 ppb
CO: 0.12 ppm

Health Recommendations:

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

12 PM

47 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 7.48 µg/m³
PM₁₀: 10.57 µg/m³
O₃: 0.050 ppm
NO₂: 0.9 ppb
SO₂: 0.9 ppb
CO: 0.11 ppm

Health Recommendations:

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

1 PM

50 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 7.93 µg/m³
PM₁₀: 10.7 µg/m³
O₃: 0.054 ppm
NO₂: 0.6 ppb
SO₂: 0.9 ppb
CO: 0.11 ppm

Health Recommendations:

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

2 PM

56 AQI

Moderate air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 8.29 µg/m³
PM₁₀: 10.96 µg/m³
O₃: 0.056 ppm
NO₂: 0.6 ppb
SO₂: 0.8 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.

3 PM

59 AQI

Moderate air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 7.1 µg/m³
PM₁₀: 9.31 µg/m³
O₃: 0.057 ppm
NO₂: 0.5 ppb
SO₂: 0.6 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

59 AQI

Moderate air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 6.49 µg/m³
PM₁₀: 8.58 µg/m³
O₃: 0.057 ppm
NO₂: 0.5 ppb
SO₂: 0.5 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

59 AQI

Moderate air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 6.29 µg/m³
PM₁₀: 8.44 µg/m³
O₃: 0.057 ppm
NO₂: 0.6 ppb
SO₂: 0.5 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.

6 PM

55 AQI

Moderate air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 6.51 µg/m³
PM₁₀: 8.8 µg/m³
O₃: 0.056 ppm
NO₂: 0.9 ppb
SO₂: 0.6 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

49 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 6.76 µg/m³
PM₁₀: 9.07 µg/m³
O₃: 0.052 ppm
NO₂: 1.6 ppb
SO₂: 0.7 ppb
CO: 0.12 ppm

Health Recommendations:

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

8 PM

45 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 6.41 µg/m³
PM₁₀: 8.45 µg/m³
O₃: 0.049 ppm
NO₂: 2.3 ppb
SO₂: 0.8 ppb
CO: 0.12 ppm

Health Recommendations:

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

9 PM

39 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 5.48 µg/m³
PM₁₀: 7.2 µg/m³
O₃: 0.042 ppm
NO₂: 2.8 ppb
SO₂: 0.7 ppb
CO: 0.13 ppm

Health Recommendations:

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

10 PM

33 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 4.98 µg/m³
PM₁₀: 6.8 µg/m³
O₃: 0.036 ppm
NO₂: 3.1 ppb
SO₂: 0.6 ppb
CO: 0.13 ppm

Health Recommendations:

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

11 PM

29 AQI

Good air quality Dominant pollutant: O₃

Details

Pollutant Concentrations:

PM_2.5: 4.77 µg/m³
PM₁₀: 6.81 µg/m³
O₃: 0.031 ppm
NO₂: 3.3 ppb
SO₂: 0.4 ppb
CO: 0.13 ppm

Health Recommendations:

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

Current Real-Time Air Quality Report

Weather Alerts and Warnings for Philadelphia

Moderate Expected Likely

Heat Advisory

Heat Advisory issued May 19 at 2:25PM EDT until May 20 at 8:00PM EDT by NWS Mount Holly NJ

May 19, 2:25 PM → May 20, 8:00 PM

WHAT: Heat index values up to 99 degrees expected.

WHERE: In Delaware, New Castle County. In New Jersey, Mercer,
Camden, Gloucester, and Northwestern Burlington Counties. In
Pennsylvania, Delaware, Eastern Chester, Eastern Montgomery, Lower
Bucks, and Philadelphia Counties.

WHEN: Until 8 PM EDT Wednesday.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.

ADDITIONAL DETAILS: Maximum heat indices near 100 degrees during
peak heating this afternoon and then again on Wednesday. Given the
intensity of this early season stretch of heat and humidity, we
are not fully acclimated to it and therefore impacts could be
greater if precautions are not taken. Showers and some
thunderstorms arrive later Wednesday afternoon and evening which
will end this early season heat.

+ Read More

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.

Updated: May 19, 11:51 PM Source: NWS Alert

Hourly Air Quality Forecast - AQI (US EPA)

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Weather Alerts and Warnings for Philadelphia

Heat Advisory

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