Surface observations

Data from the National Weather Service, made available here by the UAlbany Department of Atmospheric and Environmental Sciences

The weather observed at PHILADELPHIA, PA (KPHL) at 02:54 AM EDT was:
  The skies were mostly clear.
  Temperature: 39F (  4C)  Dewpoint:  21F ( -6C)  Relative Humidity:  48%
  Winds from the W  (260 degs) at 12 mph.
  Pressure: 1017.2 millibars.  Altimeter:30.04 inches of mercury.
  The prevailing visibility was 10 miles.