Heat Waves in the United States: Definitions, Patterns, and Trends

by Tim Storer

Heat waves have impacts on a variety of industries and demographics throughout the world, and they are much scientific interest. In the United States, research has been done to study the trends in heat wave intensity and frequency. Unfortunately for the researchers, there have traditionally been many varying definitions of “heat waves,” in previous research, and additional work was required to standardize the data so that it could be analyzed for trends. The varying definitions are due to a multitude of interested parties, such as health researchers measuring heat waves that break a dangerous threshold, versus climate scientists tracking temperatures that are in high percentiles. Having compiled all the different definitions, the recent research showed mostly positive trends in the number of heat wave days per year in most of the United States, with the strongest increases in the Southeast and Great Plains regions (Smith et al. 2013). This approach is especially powerful, because by combining many different measures of heat waves, the study is likely to eliminate oversight that any individual measure may have. Continue reading