Paula Brown and Arthur DeGaetano

Journal of Applied Meteorology and Climatology

Published date January 9, 2013

Trends in U.S. Surface Humidity, 1930–2010

  • Examines US hourly surface observations at 145 stations to identify annual and seasonal changes in temperature, dewpoint, relative humidity, and specific humidity since 1930
  • Finds that average long-term trends (1930–2010) indicate that temperature has warmed but that little change has occurred in dewpoint and specific humidity
  • Finds that trends since 1947 indicate that the warming of temperatures has coincided with increases in dewpoints and a moistening of specific humidity
  • Finds that this moistening is especially pronounced during the summer in the Midwest
  • Finds that for the nation, trends in relative humidity show little change for the period 1947–2010, during which these data are more homogeneous
  • States that moistening has occurred throughout the central United States while other regions have experienced drying