Weather + Climate

 

Last Update: 11 July 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 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).

 

Current Conditions

Below is the same chart that appears to the right (desktop) or below the article (mobile). All data is updated on an hourly basis. The two right-most data points show today’s average temperature and the normal average temperature for today. The average temperature is simply the high for the day plus the low for the day, divided by two. NOAA’s definition of “normal” is based on data collected between 1980 and 2010. The third chart on the right (desktop) or below (mobile) shows how temperatures up to this point in the month compare to historical temperatures up to this point in the month going back to 1930. Since our graphs update on an hourly basis, the ranking may change throughout the day as today’s latest temperatures get incorporated into the historical comparison.

The chart with the colored dots on the right (desktop) or below (mobile) shows the average month-to-date temperature for all years going back to 1930. The black star represents 2018. The month-to-date average temperature is the average temperature from the first of the month through today. For example, on June 30 there were 8 years with warmer June 1 to June 30 (month-to-date) average temperatures than June 1 to June 30, 2018. That makes June 1 to June 30, 2018 the 9th warmest June 1 to June 30 on record, which is reflected on the bottom chart.


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 historical 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.

Georgia Average Temp, Jan 17 to June 18

 

June Analysis

Temperatures throughout Georgia were 1.3°F above average between January and June 2018 making that period the 28th warmest 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.


June Analysis

June temperatures were 2.5°F above average in Atlanta. Only 5 of the previous 18 months have had below average temperatures.


 Atlanta Average Precipitation

The chart below shows the actual monthly precipitation recorded at Atlanta Hartsfield International Airport (blue bar) versus the average monthly precipitation (blue line).  All data is from the National Weather Service Forecast Office in Peachtree City, GA.

May Analysis

May precipitation was 1.18 inches above average, which pushed the 2018 precipitation surplus close to 4 inches.


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.

 

June Analysis

We’ve seen about average rainfall so far this year and June was no different. Drought conditions that had crept into eastern Georgia earlier in the year have subsided and all districts remain drought-free.

 


 

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