The USHCN2 “raw” monthly temperature data shows that the period ending June, 2012 is the hottest twelve month period on record in the US, beating 1934 by a little over 0.1 degrees.
This may be bogus, because the 1930s USHCN2 monthly “raw” data is about 0.2 degrees lower than the daily raw data.” For example, the monthly data shows 11/1934 as 55.281, but the daily data shows it as 55.4316 – which would make the period ending 11/1934 the hottest 12 month period on record.
Most of the hottest 12 month periods in the USHCN2 database occured during the 1930s. USHCN2 only goes back to 1895, and does not include the 1884/1885 warm period which the daily temperature records show was the hottest.
With cooler temperatures prevailing now, it is unlikely that the raw full year 2012 will beat 1934.
Month Year Temperature 6 2012 55.4049 5 2012 55.3776 11 1934 55.281 8 1934 55.1797 3 1935 55.1331 12 1921 55.1261 7 1934 55.0692 11 1921 55.0463 4 2012 55.0413 12 1998 55.0358 10 1934 54.9995 1 1932 54.999 12 1934 54.9941 12 1931 54.988 5 1934 54.9688 10 2000 54.9686 2 1932 54.939 2 1935 54.9334 4 1999 54.9253 6 1934 54.9238