Last Update: 01 Nov 2017
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 left side of the homepage. All data is pulled from the National Oceanic and Atmospheric Administration (NOAA) websites and is updated monthly. We’ll be adding much more data and information in the future.
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 54.8 ºF (blue bar). Historically, the average temperature during that period is 47.4 °F (blue 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. The average temperature in Georgia between January 1, 2017 and June 30, 2017 was 67.3 °F while the historical average temperature for that time period is 63.8 °F. In 123 years of record keeping, January 1, 2017 to June 30, 2017 was the warmest such time period of any year.
Nothing new for September. Despite the month ending with a relatively average final temperature mark in north Georgia (thanks to a cool beginning of the month and warm end of the month), it looks like 2017 will be either the warmest year on record or 2nd warmest year on record. This will continue the trend we’ve seen over the past decade or so with each year eclipsing the previous year as the warmest on record.
City of Atlanta Average Temperature
The figure below shows the actual average monthly temperatures at Atlanta Hartsfield International Airport for 2017 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 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.
Despite ending the month with temperatures well-below average, October’s monthly average temperature was 65.7 °F, which was 2.4 °F above the historical normal average temperature for October. As illustrated in the chart below, the beginning of the month had several days with temperatures 10-15°F above normal while temperatures in the latter half of October were mostly below 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.
Rainfall was .46 inches above average for October, which pushed the yearly rainfall surplus to 5.35 inches.
Drought data will be updated on 06 Oct 2017.
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.
NOAA has divided Georgia into nine climate divisions and PDSI values are given for each district. Most of metro Atlanta is in District 2 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. Dryer conditions in District 2 and 3 will result in less water flowing into Lake Lanier while wetter conditions in South Georgia can result in less water being released from Lake Lanier.
Chart 1, below, shows the PDSI values from Jan 1, 2017 – July 31, 2017 for each district. Districts 1 and 2 experienced moderate drought conditions while District 3 experienced extreme drought conditions during this time period.
Chart 2 shows the PDSI values for each district during the same time period in 2016. There is no error with that chart: each district experienced mid-range or normal conditions between Jan 1, 2016 and July 31, 2016.
Finally, chart 3 shows the percent change between 2016 PDSI values and 2017 PDSI values. Each district experienced drier conditions between Jan 1, 2017 and July 31, 2017 than they did during that same time period in 2016. District 8 saw the greatest percent change in PDSI values, though District 3 went from mid-range/normal in 2016 to extreme drought conditions in 2017.