Although the public uses "Astronomical" definitions for the seasons, these dates can vary from year to year. For example, Astronomical Spring begins this year on March 20 but the start ranges from March 20-22 over time. Meteorologists and climatologists use a three month time span to define the seasons.
The meteorological and climatological seasons are
Winter: December through February
Spring: March through May
Summer: June through August
Autumn: September through November.
The following maps show the Winter 2012-12 climate summary maps for the conterminous U.S. and the High Plains Region.