WRAL WeatherCenter Blog

Hottest summer ever? Certainly feels like it!

Posted August 21, 2010 7:07 a.m. EDT
Updated August 21, 2010 7:09 a.m. EDT

A graph of the number of hours spent in various heat index categories per year from 1972 through 2010 (YTD as of 8/20).  (Courtesy: NC State Climate Office)

Many electrons have been spent — and many more will be used — to talk about whether this has been the hottest summer on record.  Certainly, we have a chance to tie or break the record for the most 90° days in a year (the old record is 83 set just three years ago in 2007).  But just how hot has it felt, including heat and the effects of humidity?

With a tip of the hat to our colleague, Brad Panovich in Charlotte, here's a look at just that.  The North Carolina State Climate Office has a tool allowing us to look at the number of hours we've spent in various categories of the heat index on a year-by-year basis.  You'll remember that the heat index is a calculation of what it feels like to our skin with both the air temperature and the effects of humidity are taken into account.  High humidity levels make it harder for our bodies to keep cool by the evaporation of sweat, making it "feel" hotter than it actually is.

So far this year, we've spent more hours with heat index values at or above 100° than in any other since 1972.  While 2007 had the most 90° days, 1999 has had the most hours with a heat index at or above 100°.  We've already beaten that mark by quite a bit, and we've still got about a month and change of summer left.