Jim Gandy is the chief meteorologist at News19 WLTX in Columbia, S.C.

Signs of a New, Hotter Normal in South Carolina

  • Sep 15, 2015

Columbia, S.C., promotes itself as being “Famously Hot.”  The slogan is meant to draw attention to the city’s facilities, attractions, and community, but it might also describe its weather and climate, which is definitely getting famously hotter.

Meteorological summer has ended for 2015 and there are signs of a new normal. It is well documented that the earth is warming and that the primary cause is the increase in heat trapping pollution in the atmosphere. Global warming does not always translate into the same amount of local warming, though.

The warming in South Carolina has not been as fast as in other parts of the country.  All seasons are warming in the U.S., but not at the same rate. The seasons showing the most warming in South Carolina are winter and summer, respectively.

Seasonal Warming in South Carolina

The warmer winters are nice, but they are causing problems for agriculture.  For example, peaches require a certain number of chilly hours in order for the trees to bear fruit.  Also, the milder winters are allowing destructive insects to move north into South Carolina.

However, summers are the biggest problem for people and agriculture.  As the climate warms, more moisture is making its way into the atmosphere. The combination of heat and humidity is creating a greater heat stress for outdoor activities. It is also a factor leading to higher energy costs.

Columbia has seen its three hottest summers on record in just the last six years. There are memories of the great heat waves of the 1950’s, but those summers don’t measure up to recent summers. Those summers had more 100 degree days, but at least there was some relief at night. That is not the case now.

A disturbing finding is that the three hottest summers have had the three highest average minimum temperatures on record. The higher low temperatures are a function of the higher moisture content of the atmosphere.

I first noticed this in 2010.  Low temperatures kept getting warmer throughout the summer.  The lowest dew point temperatures were frequently near 75° making the low temperature 77° or higher.  I found that the low temperatures failed to go below 77° on 23 days that summer.  The previous record for such an observation was 10 days in 2003.  Thus, 2010 shattered that record.  Comparing all summers I have found that the summer low temperatures were warming faster than the high temperatures.

A similar result occurred the following year in 2011, but in this case the high temperatures were hotter, thus replacing 2010 as the hottest summer on record.

This year also turned out to be a hot summer. Columbia tied with 1986 for fourth place for the number of 100-degree days (17).  It was also the third hottest summer on record even though only one high temperature record was broken.  Again, it was the average low temperature that made the difference as it was the third highest average on record.

These hot summers are having an effect on people’s health. The heat stress is leading to lower productivity. Heat related heat problems are also noticeable among the young and old.

I began a segment in 2014 called Gandy’s Garden. The idea grew out of the drought in California and the impact that was having on the well-being of consumers. This summer brought to light issues the hot summer was having on agriculture.

First, we had near normal rainfall this summer yet much of the area slipped into drought.  I found that 76 percent of the rainfall in the Columbia area occurred on just 7 days.  This was an example of the increase in the number of heavy rain events.  Corn production suffered greatly on non-irrigated fields.  In addition, the heat stress limited the effects of pollination on corn crops.  This was evidence even in Gandy’s Garden.

The heat affected tomato production and many gardeners had trouble with their tomatoes.  Columbia had the sixth highest number of days above 95° and those temperatures affect the pollination of tomatoes.

South Carolina may not be warming as fast as the planet, but it is warming.  The effects of this warming are clear, but subtle.  The trend continues and recent summers are a window into the future.  Thus, we are looking at a new normal in the making.  What is extreme now will likely be normal in the near future.