The National Weather Service says 2009 has seen the coldest July since the official recording station was moved away from the lakefront in 1942. The average temperature this month in Chicago has been a mere 68.9 degrees.
Even in the years before 1942, when the National Weather Service recorded temperatures at the cooler lakefront, there are only three years that had colder Julys through the 26th.
There have also been far more days than usual with high temperatures less than 80 degrees this year. In 2009, there were 13 days where the temperature did not exceed 80 degrees. Only three Julys in the past 67 years have had more days in Chicago with highs less than 80 – there were 18 such days in 1992, and 14 in 1996 and 2000.
We have also failed to reach 90 degrees at any time this month.