- For the 2009 summer, the average temperature of 71.7 degrees F was 0.4 degree F below the 20th Century average. The 2008 average summer temperature was 72.7 degrees F.
- A recurring upper level trough held the June-August temperatures down in the central states, where Michigan experienced its fifth, Wisconsin, Minnesota, and South Dakota their seventh, Nebraska its eighth, and Iowa its ninth coolest summer. By contrast, Florida had its fourth warmest summer, while Washington and Texas experienced their eighth and ninth warmest, respectively.
- The Michigan, Wisconsin, Iowa and Minnesota region experienced its sixth coolest summer on record. Only the Northwest averaged above normal temperatures.