The link to that data is strangely no longer accessible.....
This is all I can find:
http://www.noaanews.noaa.gov/stories2007/s2862.htm
"For the contiguous U.S., April's average temperature was 51.7 degrees F (10.9 degrees C), which was only 0.3 degrees F (0.2 degrees C) below the 20th century mean (based on preliminary data). "