Chicago’s Official Records
 
Temperature (in degrees Fahrenheit)
            
  Highest Temperature…………………….... 105 degrees on July 24, 1934
  Lowest Temperature.……………………....   -27 degrees on January 20, 1985
     
  Warmest Month…………………………......  81.3 degrees in July 1955
  Coldest Month……...…………………….....   10.1 degrees in January 1977
     
  Warmest Season………………………….... 76.4 degrees in Summer of 1955
  Coldest Season……..……………………... 18.3 degrees in Winter of 1903-04
     
  Warmest Year...………………………….....   54.4 degrees in 1921
  Coldest Year………..……………………..... 45.1 degrees in 1875
     
  Highest Dew Point…………………………. 83 on July 29th-30th 1999 
  Lowest Relative Humidity............................. 13%: 5/10/1934; 4/8/1971; 4/11/1956
                 
                        
            
Precipitation (in inches)
            
  Wettest Year…..…………………………..... 50.86 in 2008
  Driest Year….……...…………………….....  22.22 in 1962
     
  Wettest Season…..………………………..... 23.48 Summer (Jun – Aug) of 1987
  Driest Season…………………………….....  1.60 Winter (Dec – Feb) of 2002 - 2003
     
   Wettest Month...…………………………..... 17.10 in August 1987
   Driest Month...……..…………………….....  0.01 in September 1979
     
  Greatest in 24 hours………………………... 9.35 on August 13 – 14, 1987
  Greatest calendar day………..…………….. 6.86 on July 23, 2011
             
            
                       
                                      
Snowfall (in inches)
 
  Seasonal (Jul – Jun) Greatest..…………… 89.7 in 1978 - 1979
  Seasonal (Jul – Jun) Least.……..……….... 9.8 in 1920 - 1921
  Winter (Dec – Feb) Greatest………………. 80.6 in 1978 – 1979
  Winter (Dec – Feb) Least…………………... 5.7 in 1930 - 1931  
     
  Greatest Total:  
            Month………………………………....... 42.5 in January, 1918
            Storm.………………………………. .... 23.0 on January 26 – 27, 1967
            24 hours.……………………………..... 20.0 on February 1-2, 2011
            Calendar Day………………………..... 18.6 on January 2, 1999
            Snow Depth………………………….... 29 inches on January 14, 1979
                                                   
                                                                                                                                    
Pressure (in inches of Mercury)
 
  Highest…………..……………………….....  30.98 on Feb 16, 1989
  Lowest……….……..……………………..... 28.70 on March 12, 1923
            
Wind (in mph)
            
  Highest Gust………………………………..   87 on February 12, 1894
  Coldest Wind Chill…..….………………….   -82 on December 24, 1983
             
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