The weather observed at PHILADELPHIA, PA (KPHL) at 03:54 AM EST was: The skies were mostly clear. Temperature: 43F ( 6C) Dewpoint: 23F ( -5C) Relative Humidity: 45% Winds from the NW (310 degs) at 9 mph. Pressure: 1010.9 millibars. Altimeter:29.85 inches of mercury. The prevailing visibility was 10 miles.