Surface observations

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

The weather observed at CHICAGO O'HARE, IL (KORD) at 05:51 PM CDT was:
  The skies were mostly cloudy.
  Temperature: 81F ( 27C)  Dewpoint:  54F ( 12C)  Relative Humidity:  39%
  Winds from the S  (190 degs) at 24 mph.
  Pressure: 1009.6 millibars.  Altimeter:29.82 inches of mercury.
  The prevailing visibility was 10 miles.