NOAA's National Climatic Data Center (NCDC) released the 1981-2010 Normals on July 1, 2011. On August 1st, 2011, the next 30 year interval of normals will start to be used in NWS climate products. The new normals will use a data period from 1981 to 2010, replacing the old period of 1971-2000.
Click here for graphs that show how the new Normals have adjusted at Duluth, MN. Similar graphs for other locations will be available soon. The main difference is that the decade of the 1970s is no longer in the 30-year average set. One thing to keep in mind is that for the Northland, the 70s was a generally cool decade.
Additional Normals products; such as frost/freeze dates, growing degree days, population-weighting heating and cooling degree days, and climate division and gridded normals; will be provided in a supplemental release by the end of 2011.
NOAA's new 1981-2010 Climate Normals are now available on the internet via File Transfer Protocol (ftp). You can access the new normals from the NCDC normals website at: 1981-2010 Climate Data from NCDC