Although the public is most familiar with the astronomical seasons and Summer would be defined as June 21 to September 20 (with some variation from year to year for the starting and ending dates), Meteorologists and Climatologists use a different definition termed "meteorological Summer" which extends from June 1 through August 31. The following two maps show the statewide rankings for Summer 2012 temperatures and precipitation. There are 118 years in the data set. Rank number 1 in precipitation is the driest and 118 would be the wettest on record. The states are shaded in color to quickly see where it was much above, above, below, much below normal as well as driest ever recorded and wettest ever recorded. No shading indicates that it was near normal. The shading on the temperature rankings map is the same process but substituting precipitation for temperature.
Summer 2012 was much above normal for temperatures for about half of the lower 48 states. Nebraska had its 3rd warmest summer on record (116th coldest out of 118 years). Nearby Wyoming and Colorado had their warmest summer on record (118th coldest out of 118 years). None of the lower 48 states experienced below normal temperatures during summer 2012.
The summer season's (June-August) nationally-averaged temperature was 74.4°F, 2.3°F above the 20th century average. Only the summers of 2011 (74.5°F) and 1936 (74.6°F) had higher temperatures for the Lower 48.
Summer 2012 was the driest on record for Nebraska, Wyoming and Washington State. However, in stark contrast the Gulf stes and southeastern states experienced above normal to much above normal precipititon. Some of NCDC summary can be found after the two maps.