The 'August Cool Snap' Theory

The cool snap predicted for later this week is no surprise to some people in the Carolinas.

Over the years, I've heard several different versions of the "August Cool Snap" theory, which states that Charlotte's brutal summer heat usually is broken -- for a few days, at least -- by cooler weather at some time during August.

I first heard about it from the late Gerry Leland, who worked at The Observer for 37 years before retiring in the 1990s. He believed the cooler temperatures came in the second week of the month.

Attorney Dick Huffman in Salisbury reminded me about the theory again Tuesday morning. He was married 30 years ago today, and he recounted how he quieted his bride-to-be's fears about a hot mid-August day by telling her the weather would be fine.

"To my amazement, it was wonderful, with highs in the upper 70s or low 80s," Huffman recalled.

He says that many years, he has noticed a spell of cooler weather sometime around his anniversary, although he says it doesn't always take place.

Meteorologists say a Canadian high pressure system will limit daytime highs to the upper 70s and lower 80s Wednesday and Thursday, and thick clouds and rain could do the same thing Friday and Saturday.

So I went back and looked at August weather over the past 10 years, and like many other statistical studies, it's a matter of interpretation, to some degree.

Do you call it a "cool spell" if daytime highs are 85 to 87 degrees, but morning lows are around 60 -- about 10 degrees below average.  Lows of 60 degrees signal very low humidity, and that would feel very nice in the middle of August.

Here is what happened the past 10 years, and I'll let you decide on this issue of the August Cool Snap.

2012 ... From Aug. 13-17, we had a stretch of days with highs in the mid 80s, but morning lows in the low 60s. Humidity levels were quite low.

2011 ... After hitting 90 or more on nine of the first 10 days of the month, it got more moderate. Morning lows on the 16th and 17th were near 60 degrees.

2010 ... Forget it!  There was nothing remotely close to a cool down.

2009 ... The high on Aug. 12 was only 74 degrees, and morning lows from Aug. 13-16 were in the mid 60s.

2008 ... The first 10 days were hot (mostly 90s), but it was a lot cooler on the 13th and 14th. Aug. 13 had a high of 76 after a morning low of 60. The next day, the high and low were 82 and 61. Temperatures stayed moderate for the next week, before turning hot again at the end of the month.

2007 ... Worse than 2010. There were six days of 100 degrees or more, and Charlotte hit at least 90 degrees every day in August.

2006 ... A definite cool down from Aug. 11-13, with a high of 73 on the 11th and morning lows in the low 60s.

2005 ... From Aug. 7-10, highs were only in the mid 80s, but it was warm at night.

2004 ... The poster child for the August Cool Snap theory.  The morning low on Aug. 7 was 50 degrees (a record), and it was 55 on Aug. 8. Daytime highs were only 80 degrees.

2003 ... The beginning of the month was moderate, with highs in the low to mid 80s. It got hot late in August that year.