On July 1, 2011 NOAA National Climatic Data Center (NCDC) released the 1981-2010 Normals, which replaces the 1971-2000 Normals. Climate Normals are the latest three-decade averages of climatological variables, including temperature and precipitation, and are updated every 10 years.
In terms of differences between the latest Normals and the previous 30 year average, the 1981-2010 Normals are approximately 0.5 degree F warmer than the 1971-2000 period. While changes from one installment of Normals to the next can provide some evidence of climate change impacts, care must be taken when interpreting changes between one Normals period and another, as there can be many factors that contribute to these differences. Factors such as observing station moves, changes in observing practices, changes in instrumentation, etc. can all contribute to Normal period differences, and are not necessarily reflective of real changes in the underlying climate signal.
The averaged annual statewide changes in minimum and maximum temperatures from the period 1971-2000 to the 1981 -2010 period are shown below. Additional information can be found on the NCDC website at: http://www.ncdc.noaa.gov/oa/climate/normals/newnormals.html