A long hot summer in Atlanta, one of the worst ever... one of the worst in memory say old timers. Well, yes and no.
The current stretch of 90 degree or higher days in Atlanta is 5. Our temperatures have been running significantly above normal for May, June, July and so far in August. What is more, the humidity levels have been much higher than normal this summer keeping the discomfort level much greater day and night with the heat index or "feels like" index often 100 or above day after day.
Compare that to the past two summers which had a notable lack of extreme heat or long 90 plus streaks. Also the humidity was normal or below-normal the past couple summers, so by comparison this summer has been brutal.
It really has not been as bad as people think, we've broken the stretches of 90 in a row several times this summer, albeit usually just for a day and usually just a degree or two below 90, it's the humidity and lack of cool off at night that has been most pronounced this summer. Birmingham on the other hand is 45-50 days of unbroken 90 or above days and counting.
It was 2007 at the peak of the drought that we had more 90s in a row than this summer, plus nine 100 days in August with a high of 104. In 2007 almost the entire month of August was well into the 90s! August 2007 opened at 92 and did not lower to 86 until the last day of the month, which included one streak of 5 100 or higher days and a streak of 4 100 or above days. That month high and low temperatures averaged 7 degrees above normal. By comparision this June was 4.6 degrees above average, July just 2.3 above-normal, and so far this month 4.3 above-average.
This summer on the other hand: well the "official" thermometer at Hartsfield had a max of 89 on August 14th (current 90+ string just 5 days) and a max of only 84 on August 2nd. Last month the longest stretch of 90+ was 13 days.
We've only had a couple days of upper 90s and a handful of 95 degree days. Since normal highs are 90 this is hardly remarkable. The hottest official temp this summer in Atlanta is 97-- twice last month, 96 twice this month.
May was also a warmer and more humid than normal month, it started being fairly consistently hot about May 22nd, though a few low 80s days still occurred late that month. But most hot weather last month and this month has been accompanied by higher than average dew points! Dew point is a measure of the moisture content in the air, if you cool the air to the dew point it reaches saturation and you get dew or fog. The higher the dew point the higher the humidity and the greater the discomfort, the higher the "feels like heat index will be.
In a typical Atlanta summer drier air aloft mixes down, and drier air out of the mountains drains into Atlanta lowering our dew point while the worst of the "sticky" air is in central and south Georgia. But the nature of upper and surface pressure and wind patterns this summer has allowed much humidity from both the Atlantic Ocean and Gulf of Mexico to lock into North Georgia. But the core of the heat dome this summer has been west and north of Atlanta from Texas to Nebraska to Alabama where records have been broken with triple digit high temps common all summer along with lots of humidity.
So in Atlanta a hot summer yes but not unusually so. It's the humidity that's made it a long summer of our discomfort.
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