Lest we forget: U.S. Weather Highlights for 2009: The Year Without a Summer

Weatherwise Magazine -- May/June 2010

June temperatures averaged three to five degrees below normal from Minnesota westward to Montana, and one to two degrees below normal from the Great Lakes into New England.

But July was one for the record books, as a vast extent of the nation measured temperatures well below the norm. The mercury averaged two to six degrees below normal from Montana to Maine and from the Great Lakes southward to northern Mississippi. Temperatures dropped into the 30s and 40s in places that seldom see such readings in midsummer. International Falls, Minnesota, notched a record minimum of 35°F on both July 12 and 13, and reported its coolest July on record. The week of July 13–19 was the coolest such period on record in Iowa, averaging 7.6°F below normal, and temperatures dropped as low as 42°F. Indiana, Illinois, and Iowa recorded their coolest July in 114 years, and the Midwest as a whole measured its coolest July. Many cities also broke records, with Madison, Wisconsin reporting its coolest July since records began in 1869.

In New York City, Central Park failed to make it to 85°F from June 1 through July 16. Simply put, this had never happened before. In Boston, every day except one registered below-normal temperatures from June 8 through July 16. However, Boston's maximum temperature of 95°F on August 18 meant that summer was not totally AWOL this year. To the west, Chicago reported its fifth-coolest summer since 1942 and only four days in the 90s, three of which occurred in late June.