According to the NOAA August 2013 was the 92nd warmest out of 119. That means only 28 were warmer.
These are the 28: 1901,1913,1934,1936,1937,1938,1943,1947,1955,1958,1959,1969,1970,1983,1984,1988,1995,1998,2000,2001,2003,2005,2006,2007,2010,2011,2012
It was cool in the east though. The numbers below are the rank out of 119.
So North Carolina (for example) was 13th warmest out of 119. Which means 107 Augusts in NC were warmer.