The beginning of fall is a cherished moment marked by cooler air and changing leaves. Determining when autumn officially begins is not a simple matter of checking a calendar, especially in a state like Georgia. The date that children return to school or stores stock pumpkin spice lattes rarely aligns with the actual shift in weather. The answer depends entirely on whether an individual is looking for a scientific definition, a data-driven metric, or the practical reality of comfortable outdoor conditions.
The Astronomical Definition
The most formal, calendar-based start of the season is marked by the Autumnal Equinox. This astronomical event occurs when the sun crosses the celestial equator, resulting in a moment where the lengths of day and night are nearly equal. The precise date shifts slightly each year, falling on either September 22nd or September 23rd.
This date signals the point in Earth’s orbit when the Northern Hemisphere begins to receive less direct sunlight, initiating seasonal cooling. The equinox is purely a function of celestial mechanics and does not account for local climate conditions. While scientifically significant, this official date rarely corresponds to a noticeable change in Georgia’s lingering heat and humidity.
The Meteorological Definition
Climate scientists and weather forecasters use a different, fixed system to define the seasons for statistical purposes. Meteorological fall is defined as the three full months of September, October, and November. This system begins precisely on September 1st and concludes on November 30th every year.
Meteorologists use fixed three-month periods to align with the annual temperature cycle and simplify the calculation of seasonal statistics. This method ensures that temperature data and climate records are comparable across different years, avoiding the slight annual shifts of the equinox. The consistent start date allows for straightforward analysis of long-term climate trends and seasonal averages.
When Georgia Actually Feels Like Fall
For most residents, the true start of fall is the moment the oppressive summer heat and humidity finally break. Georgia’s humid subtropical climate means that September often feels like an extension of summer, with average high temperatures frequently reaching the upper 80s or low 90s. The practical transition to autumn weather typically lags significantly behind both the astronomical and meteorological start dates. The noticeable drop in temperature and accompanying relief usually begins in mid-to-late October across much of the state. This period is when average daytime high temperatures consistently settle into the comfortable low to mid-70s, making outdoor activities more enjoyable.
The timing of this relief varies considerably between North Georgia and the southern coastal plains. Mountain regions, including areas around Atlanta, Blue Ridge, and Amicalola Falls, experience a cooling trend two to three weeks earlier than the rest of the state. These higher elevations receive consistent dips into the 40s and low 50s at night by early to mid-October, allowing for earlier seasonal comfort.
Conversely, the coastal and southern plains may not experience consistent relief until early November. For these regions, persistent humidity is the last factor to dissipate, often keeping nighttime temperatures elevated through the end of October. The true “jacket weather” is often reserved for November for the majority of the state. This delay is why the official calendar dates feel so disconnected from the physical reality of the season for most Georgians.
Peak Foliage Timing Across the State
The changing color of leaves is another indicator of the season’s arrival, though it is geographically variable. Color change is triggered by two main environmental factors: shortening daylight hours and cooler nighttime temperatures. Chlorophyll production slows as days grow shorter, allowing underlying pigments like carotenins and anthocyanins to become visible.
In Georgia, the progression of color starts in the highest elevations and moves southward. The North Georgia Mountains, including popular destinations like the Cohutta Wilderness and Tallulah Gorge, reach their peak foliage viewing period from the last week of October through the first week of November. This timing aligns with the earlier temperature drops in the mountain regions.
Central Georgia, encompassing the Atlanta metropolitan area and cities like Macon and Columbus, experiences its peak color significantly later. Foliage in these lower-lying areas typically reaches its most vibrant stage between the middle and end of November. The visual autumn experience often extends right up to the Thanksgiving holiday.