"Sticky" Southeast

The more water in the atmosphere, the less easily sweat evaporates from your body, and the harder it is to keep your body at a comfortable temperature. The dewpoint temperature is one of the best indicators of how “uncomfortable” hot weather is, and when the dewpoint temperature exceeds 65 degrees Fahrenheit, most people consider the weather to be “sticky.”

In the Southeastern United States, while the average temperature during the fall has increased only slightly over the past half century, the average dewpoint temperature during the fall has been rising by about one degree Fahrenheit per decade. For the nation as a whole, the average annual dewpoint temperature has been rising by about 0.54 degrees Fahrenheit per decade.

(Sources: Gaffen, DC and Ross, RJ. “Climatology and Trends of U.S. Surface Humidity and Temperature.” Journal of Climate: Volume 12, Issue 3, pp. 811-828 and Roderick, ML et al. “The Cause of Decreased Pan Evaporation over the Past 50 Years.” Science 298, 1410 (2002).)