A Comparison of 30-yr Climatic Temperature Normals for the Southeastern United States

Thirty-year climatic normals are an integral part of climate and climate assessment, but they are typically not used to address issues of climatic change. For 104 stations within the southeastern United States, I analyze spatial parameters of the two most recent 30-yr temperature normals (1961-1990, 1971-2000) to illustrate the utility of 30-yr normals for an assessment of climatic change. My comparison of the two normal periods shows that the Southeast as a whole has experienced a small (0.10°C) but significant increase in average temperature. However, of the seven physiographic provinces examined, only the lower Coastal Plain has experienced a significant increase in temperature. My analysis of urban versus rural sites produced mixed results on the potential impacts of urbanization and the associated heat island effects on the observed changes in temperature. While some long-term analyses of the thermal climate of the Southeast have shown the region to be cooling, my results suggest that the thermal climate of the southeastern United States since 1961 is stable or slightly warming.