September in North Georgia always seems to have an identity crisis. It’s the one month where you can easily find yourself blasting the air conditioner in the afternoon and reaching for a light jacket by evening. For most of us living across metro Atlanta and up into the mountains, September is the bridge between summer’s muggy heat and fall’s crisp air. Early in the month, it usually feels a lot like late August. Afternoon highs average in the mid-80s, and the humidity still clings to the air.
But as the days get noticeably shorter, the weather takes a turn toward fall. By the end of the month, average afternoon temperatures drop to the upper 70s, and nighttime lows fall to upper 50s.
Rainfall also starts to change. The endless cycle of afternoon pop-up thunderstorms that keeps us indoors during July and August finally begins to fizzle out. September is historically one of the drier months of the year, averaging around 3 to 3.5 inches of rain. This drop in rain brings some of the clearest, most beautiful blue skies you’ll see all year.
Still, September isn’t always smooth sailing. The month can deliver wild swings in weather, usually driven by two very different extremes: tropical storms and late-summer heatwaves.
September is the absolute peak of the Atlantic hurricane season. Even though North Georgia is miles from the coast, passing tropical systems often push inland, bringing massive amounts of moisture with them. When those heavy rain clouds hit our local hills and mountains, they can dump dangerous amounts of water.
Many locals still remember the historic floods of September 2009. A slow-moving tropical storm setup parked over the region and dumped over 20 inches of rain in some areas west of Atlanta over a single week. Rivers overflowed, neighborhoods flooded, and major highways were shut down.
A more recent reminder came in late September 2024, when the remnants of Hurricane Helene tracked right over Georgia. Atlanta saw a record-shattering 11 inches of rain in just two days, causing flash flooding, knocking down trees in rain-soaked soil, and leaving power outages across the area.
While our Super El Nino continues to shut down the Atlantic hurricane season with its powerful wind shear, the Gulf is still open for business and the water temperatures there are broiling.
On the flip side, when the tropics stay quiet, North Georgia can easily lock into a stubborn stretch of high heat. Strong high-pressure systems can trap hot air over the South, making mid-September feel like the middle of July.
During these heatwaves, temperatures can easily climb into the mid-to-upper 90s. Back in September 2019, Atlanta hit an all-time monthly record of 99. We saw similar heat in late September 2024, when high temperatures repeatedly broke daily records by reaching 97. When these dry, hot spells stretch on for weeks, they can quickly dry out lawns and gardens, leading to sudden fall droughts. The Climate Prediction Center’s September Outlook is calling for above average temperatures with above average rainfall.
Despite the potential for surprises, September remains one of the best times of year to be outdoors in North Georgia. As humidity levels drop during the second half of the month, the air clears up, making it a great time for weekend trips to the North Georgia mountains, early fall festivals, or just sitting out on the back porch.
Whether September brings a few final hot summer days or an early taste of autumn breezes, one thing is certain: the long, hot Southern summer is officially on its way out. After our August heat wave, l’m ready!
In looking further ahead, with our Super El Niño, expected to be the strongest in recorded history, there are good signals in all the major models, of a cold winter for the Southeast. With above average precipitation likely, the signals for winter storms, not just snow but ice too, are in the outlooks.
Of course, winter storms play out as they see fit and there is no telling what they could bring. The model is just telling me our chances for snow this winter are pretty good. We shall see!
Graphic: courtesy NWS
