Weather + Climate

 

Last Update: 06 April 2018

Monthly weather and climate data can be found here for the State of Georgia and the City of Atlanta. Quick data points and rankings are posted on the right side of the homepage (below posts for mobile users). All data is pulled from the Southeast Regional Climate Center and the National Oceanic and Atmospheric Administration (NOAA) websites and is updated on a daily and monthly basis. Georgia temperature data and drought data for the previous month is released by NOAA several days into the new month (ex: January data is released around Feb 7th).

State of Georgia Average Temperature

The figure below shows the average temperature up to that point in the year for the State of Georgia versus the historical 20th Century Average for that time period. Average daily temperatures are calculated by adding the high temperature to the low temperature and dividing by two. All the daily average temperatures are then used to determine the monthly average temperature.

NOAA has provided a ranking tool to put the data into greater context. Using 123 years of recorded data, the tool shows you how data for a particular time period compares to historical data for that time period.

The chart below uses the Year-to-Date feature to show how warm or cool the year has been up to that point compared to previous years up to that point. For example, the average temperature in Georgia from January 1, 2017 to February 28, 2017 was 54.8ºF (orange bar). Historically, the average temperature during that period is 47.4 °F (black line). This is a departure from the historical average of +7.4 °F. In 123 years of record keeping, January 1, 2017 to February 28, 2017 was the 3rd warmest such time period of any year.

GA Average Temperature Jan 17 to March 18

 

March Analysis

March temperatures throughout Georgia were 1°F below the 20th Century average. This pushed the year-to-date temperature ranking (Jan 1, 2018 to March 31, 2018) to 28th in terms of warmth. Despite a very cold January and a normal-to-cold March, February was so warm that year-to-date temperatures are still 1.9°F above average. Last year at this time Georgia was experiencing it’s warmest Jan 1 to March 31 on record.

 

City of Atlanta Average Temperature

The figure below shows the actual average monthly temperatures at Atlanta Hartsfield International Airport versus the normal average monthly temperatures. The numbers above each bar represent the difference between the actual average monthly temperature the normal average monthly temperature. For example, in April 2017 the actual average monthly temperature was 67.8 °F and the normal average monthly temperature was 62.0°F. The average temperature was therefore 5.8°F above normal. The Year-to-Date is the average of the actual and normal monthly temperatures from January 1st to the end of the previous month. All data is from the National Weather Service Forecast Office in Peachtree City, GA.

 


March Analysis

March temperatures in Atlanta were 0.8°F below average. We saw a fairly even mix of above average and below average temperatures throughout the month. Due to February’s temperatures being 10°F above average, the year-to-date average temperature in Atlanta is still over 2°F above normal.

Atlanta Average Precipitation

The chart below shows the actual monthly precipitation recorded at Atlanta Hartsfield International Airport (blue and white bar) versus the average monthly precipitation (blue line). The numbers above the bars represent the difference between the actual rainfall and the average rainfall for that time period. For example, rainfall in January 2017 was 8.18 inches while the average rainfall is 4.20 inches. The difference is +3.98 inches. All data is from the National Weather Service Forecast Office in Peachtree City, GA.

 

March Analysis

March precipitation was about average at .05 inches above normal. Atlanta is .5 inches above normal precipitation levels for the year.

 

Drought Conditions

The Palmer Drought Severity Index (PDSI) is a widely used model designed to predict drought conditions. The PDSI has its advantages and disadvantages, but NOAA and state and local governments use it to assess drought conditions over time. Negative numbers correspond to drier conditions while positive numbers correspond to wetter conditions. A PDSI value of -4.0 or below corresponds to extreme drought conditions.

Each state is divided into climate divisions with Georgia having nine division. They are numbered from northwest to southeast; metro Atlanta is in District 2 (second from top left) as is Lake Lanier, one of the state’s most important reservoirs. Drought conditions both upstream and downstream of Lake Lanier will influence the reservoir’s water levels. Drier conditions in District 2 and 3 will result in less water flowing into Lake Lanier while wetter conditions in south Georgia and Florida can result in less water being released from Lake Lanier. Tensions in the water wars between Georgia, Florida, and Alabama escalate as drier conditions increase in the southeast region. Below is a GIF of PDSI values for every climate division the country.

 

March Analysis

Drought conditions have crept back into the eastern portions of Georgia. Districts 3, 6, and 9 are currently experiencing moderate drought conditions. Atlanta, though, has continued to see average to above-average rainfall over the past 15 months (see chart above).

 


 

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