Last updated August 20, 2019

Contiguous US summer maximum temperature and heat stress trends in CRU and NOAA Climate Division data plus comparisons to reanalyses

  • States that warming is a major climate change concern, but the impact of high maximum temperatures depends upon the air’s moisture content.
  • Tracks trends in maximum summertime temperature, moisture, and heat index over three time periods: 1900–2011, 1950–2011, and 1979–2011
  • Finds that these trends differ notably from annual temperature trends
  • Finds that maximum temperature trends tend towards warming that is stronger over the Great Lakes, the interior western and the northeastern contiguous United States
  • Finds that a warming hole in the Midwest generally decreases in size and magnitude when heat stress trends are calculated because the region has increasing moisture
  • Finds that moistening in the northeast amplifies the heat stress there, and that moisture trends are less clear elsewhere the moisture trends are less clear
  • Finds that drying over northern Texas (after 1996) translates into decreasing heat stress there