The graphic up top, borrowed from NOAA's latest State of the Climate Report, really encapsulates everything there is to know about last month's unprecedented temperatures, but here's the relevant bit from the Administration for those of you itching for hard figures:
The average temperature for the contiguous U.S. during July was 77.6°F, 3.3°F above the 20th century average, marking the warmest July and all-time warmest month on record for the nation in a period of record that dates back to 1895. The previous warmest July for the nation was July 1936, when the average U.S. temperature was 77.4°F.
Last month's temperatures make the January—July 2012 period the hottest first seven months of any year on record for the lower 48. They also make the August 2011—July 2012 period the warmest 12-month period of any 12-months on record for the contiguous U.S., breaking the record that was set just last month. Weird. Looks like that Koch-funded study might be onto something.