Climate zones of the conterminous United States defined using cluster analysis

A regionalization of the conterminous US is accomplished using hierarchical cluster analysis on temperature and precipitation data. The "best' combination of clustering method and data preprocessing strategy yields a set of candidate clustering levels, from which the 14-, 25-, and 8-cluster solutions are chosen. Collectively, these are termed the "reference clusterings.' At the 14-cluster level, the bulk of the nation is partitioned into four principal climate zones: the Southeast, East Central, Northeastern Tier, and Interior West clusters. Many small clusters are concentrated in the Pacific Northwest. The 25-cluster solution can be used to identify the subzones within the 14 clusters. At that more detailed level, many of the areally more extensive clusters are partitioned into smaller, more internally cohesive subgroups. -from Authors