Published on 03/11/10

Bitter winter shakes Georgians

By David E. Stooksbury, Ph.D.

This winter was unusually cold and wet across Georgia, causing the heating demand for buildings to soar.

Climatological winter runs from December 1 to the last day in February. This winter was typical of an El Niño one for Georgia -- but on hyperdrive. The average mean daily temperature was extremely cold statewide. The daily mean temperature is calculated by taking the daily maximum temperature plus the daily minimum temperature then dividing the sum by two.

This past winter will be remembered for its long periods of below-normal temperatures. It wasn’t that Georgia experienced long periods of bitterly cold temperatures in the single digits. It was the lack of the typical warm periods between the cold periods.

The average mean temperature in north Georgia this winter was near the fourth percentile, depending on the location. Locations in south Georgia experienced mean winter temperatures near the seventh percentile. At the fourth percentile, 96 out of 100 winters would be warmer. At the seventh percentile, 93 out of 100 winters would be warmer.

The average daily minimum temperatures for the winter were around the tenth percentile statewide, except around Savannah, where the average minimum temperatures were near the fifth percentile. At the tenth percentile, 90 out of 100 winters would be warmer.

While the daily minimum temperatures were on average cold, it was the daily maximum temperatures that were the most impressively cold.

At locations across the southern half of Georgia, the average daily maximum temperatures were either the first or second percentiles. At the first percentile, 99 years out of 100 would be warmer. Across the northern half of Georgia, the average daily maximum temperatures were around the fifth percentile, depending on location.

The winter as a whole was very wet across the state, especially in December. In January and February, south Georgia was abnormally wet. However, rainfall for January and February across the northern half of the state was near normal to slightly below normal.

Because of the cold temperatures, heating demand was much higher than normal.

Across north Georgia, heating demand for Athens was 20 percent above normal. Atlanta was 22 percent above normal. Compared to last winter, heating demand in Athens was 32 percent higher and in Atlanta 36 percent higher.

The heating demand is based on heating degree days, which reflects the amount of energy needed to heat a building to a comfortable level considering the daily outside temperature.

In middle Georgia, heating demand for this winter was 32 percent above normal in Columbus, 23 percent above normal in Macon and 19 percent above normal in Augusta. Compared to last winter, heating demand in Columbus was 42 percent higher, 42 percent higher in Macon and 40 percent higher in Augusta.

Along the Georgia coast, heating demand for this past winter was 15 percent above normal in Savannah and 24 percent above normal in Brunswick. Compared to last year, heating demand in Savannah was 35 percent higher and 46 percent higher in Brunswick.

The heating demand in Alma, in south Georgia, was 40 percent higher than normal and 38 percent higher than last year.

Up-to-date weather information is available at University of Georgia automated weather station network Web site Historic climate data is available from the State Climate Office Web site

David Emory Stooksbury is associate professor of Biological and Agricultural Engineering at University of Georgia's College of Agricultural and Environmental Sciences.