Cobb climate almanac & weather forecast for Sunday, July 21, 2024

Cobb weather September 7: Photo of cloudy skies above a residential street

The National Weather Service forecasts mostly cloudy skies here in Cobb County on Sunday, July 21, 2024, with a high near 86 degrees.

The National Weather Service has issued a hazardous weather outlook for Cobb County and other parts of the region due to scattered thunderstorms that will occur in northern and central Georgia today, with a peak in activity expected between 2 p.m and 8 p.m. The strongest storms may produce frequent lightning, bursts of heavy rainfall, and gusts near 40 mph.

What you will read in this article

  1. The extended forecast for Cobb County
  2. Last month’s climate summary for the metro Atlanta region
  3. The climate almanac for metro Atlanta
  4. What the National Weather Service is, and what it does

What does the extended forecast have in store?

This forecast is centered on Dobbins Air Reserve Base in Marietta.

Today

Showers and thunderstorms likely, mainly between 3 p.m and 5 p.m. Mostly cloudy, with a high near 86. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 60 percent. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Tonight

Showers and thunderstorms likely, mainly between 7 p.m and 10 p.m. Mostly cloudy, with a low around 69. South wind around 5 mph becoming calm. Chance of precipitation is 60 percent. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Monday

A chance of showers and thunderstorms before 11 a.m, then showers likely and possibly a thunderstorm between 11 a.m and 2 p.m, then showers and thunderstorms likely after 2 p.m. Mostly cloudy, with a high near 86. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 70 percent.

Monday Night

Showers and thunderstorms likely, mainly before 8 p.m. Mostly cloudy, with a low around 69. Southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 60 percent.

Tuesday

Showers and thunderstorms likely, mainly after 2 p.m. Partly sunny, with a high near 87. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 70 percent.

Tuesday Night

Showers and thunderstorms likely, mainly before 8 p.m. Mostly cloudy, with a low around 69. Chance of precipitation is 60 percent.

Wednesday

Showers and thunderstorms likely, mainly after 2 p.m. Mostly cloudy, with a high near 85. Chance of precipitation is 70 percent.

Wednesday Night

Showers and thunderstorms likely, mainly before 2 a.m. Mostly cloudy, with a low around 69. Chance of precipitation is 60 percent.

Thursday

Showers and thunderstorms likely, mainly after 2 p.m. Mostly cloudy, with a high near 83. Chance of precipitation is 70 percent.

Thursday Night

Showers and thunderstorms likely, mainly before 8 p.m. Mostly cloudy, with a low around 69. Chance of precipitation is 60 percent.

Friday

Showers and thunderstorms likely. Mostly cloudy, with a high near 85. Chance of precipitation is 60 percent.

Friday Night

Showers and thunderstorms likely. Mostly cloudy, with a low around 70. Chance of precipitation is 60 percent.

Saturday

A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 87.

What was the climate like in the latest reporting period?

The NWS climate summary for metro Atlanta has now been updated with June 2024 figures.

In an article entitled What is the Difference between Climate and Weather?, the National Ocean Service describes the difference as follows:

“Weather is what you see outside on any particular day. So, for example, it may be 75° degrees and sunny or it could be 20° degrees with heavy snow. That’s the weather.

“Climate is the average of that weather. For example, you can expect snow in the Northeast in January or for it to be hot and humid in the Southeast in July. This is climate. The climate record also includes extreme values such as record high temperatures or record amounts of rainfall. If you’ve ever heard your local weather person say “today we hit a record high for this day,” she is talking about climate records.

“So when we are talking about climate change, we are talking about changes in long-term averages of daily weather. In most places, weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season. Climate, however, is the average of weather over time and space.”



The climate report for the Atlanta area for the previous month shows how much departure from the average temperatures that month represents. The average temperature for a date is the average over a 30-year period.

DateMaxMinAverageDeparture from normPrecipitation
2024-06-01786571.5-3.60
2024-06-028567760.60.06
2024-06-038969793.4T
2024-06-048670782.2T
2024-06-0586727930.17
2024-06-06857077.51.30.1
2024-06-078870792.60
2024-06-08876375-1.60
2024-06-09937081.54.70
2024-06-1085697700.4
2024-06-11876475.5-1.70
2024-06-128971802.60
2024-06-139072813.40
2024-06-14957283.55.80
2024-06-15977686.58.60.02
2024-06-16967585.57.40
2024-06-179375845.7T
2024-06-189173823.60
2024-06-198971801.40
2024-06-20907381.52.80
2024-06-219371823.10
2024-06-2298748670
2024-06-23987787.58.30
2024-06-249775866.70.21
2024-06-259872855.60
2024-06-261007587.57.90
2024-06-279175833.3T
2024-06-289175833.20.13
2024-06-29917683.53.60.65
2024-06-3097778770

Climate Almanac for metro Atlanta

This almanac provides information on past climate conditions for today’s date, July 21, allowing a comparison to current weather. 

Simply put, it helps you see what the weather would typically be like on this day, according to historical data.

Daily DataObservedNormalRecord HighestRecord Lowest
Max TemperatureM90102 in 198676 in 1920
Min TemperatureM7280 in 188161 in 1929
Avg TemperatureM81.288.5 in 199371.5 in 1929
PrecipitationM0.144.03 in 18990.00 in 2019
SnowfallM0.00.0 in 20230.0 in 2023
Snow DepthM0 in 20230 in 2023
HDD (base 65)M00 in 20230 in 2023
CDD (base 65)M1624 in 19937 in 1929
Month-to-Date SummaryObservedNormalRecord HighestRecord Lowest
Avg Max Temperature92.290.097.1 in 198081.1 in 1892
Avg Min Temperature74.871.675.9 in 198064.2 in 1967
Avg Temperature83.580.886.5 in 198072.9 in 1967
Total Precipitation5.433.4114.34 in 20050.17 in 1995
Total Snowfall0.00.0T in 20010.0 in 2024
Max Snow Depth0T in 19420 in 2024
Total HDD (base 65)004 in 18920 in 2024
Total CDD (base 65)376332458 in 1980171 in 1967
Year-to-Date SummaryObservedNormalRecord HighestRecord Lowest
Avg Max Temperature74.572.175.6 in 201265.9 in 1895
Avg Min Temperature55.452.655.9 in 201746.0 in 1940
Avg Temperature64.962.465.7 in 201256.3 in 1940
Total Precipitation34.1529.1447.00 in 191214.14 in 1986
Total Snowfall (since July 1)0.00.0T in 20010.0 in 2024
Max Snow Depth (since July 1)0T in 19420 in 2024
Total HDD (since July 1)004 in 18920 in 2024
Total CDD (since Jan 1)128110161281 in 2024577 in 1961

Period of Record:

  • Max Temperature : 1878-10-04 to 2024-07-20
  • Min Temperature : 1878-10-04 to 2024-07-20
  • Precipitation : 1878-10-01 to 2024-07-20
  • Snowfall : 1928-12-25 to 2024-07-20
  • Snow Depth : 1928-12-25 to 2024-07-20

For much more information on the climate in our area, visit the NWS Climate FAQ for the Atlanta area.

What does the National Weather Service do?

The National Weather Service (NWS) is a part of the National Oceanic and Atmospheric Administration (NOAA).

The NWS describes its role as follows:

“The National Weather Service (NWS) provides weather, water, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy. 

“These services include Forecasts and Observations, Warnings, Impact-based Decision Support Services, and Education in an effort to build a Weather-Ready Nation. The ultimate goal is to have a society that is prepared for and responds to weather, water and climate events.”