NOAA claims that July, 2012 was the hottest month in US history and that July temperatures are increasing.
The CRUTEM4 map below flashes between July 1936 and July 2012, with 1936 being the image that has the large +5C area in the upper midwest. As you can see, July 1936 was much hotter.
This agrees reasonably well with the original Weather Bureau map from 1936.
The graph below shows the raw US HCN data before NOAA tampered with it. July temperatures are decreasing, not increasing – and July of 1936 was much hotter than July 2012.
NOAA turned a cooling trend into a warming trend by massively tampering with the raw data, as seen below. They cooled 1936 and 1934 by almost 1.5 degrees, in an important propaganda effort to make it look like global warming was affecting the US.