September in Great Smoky Mountains National Park is a good month: highs around 81°F, lows around 57°F. Crowds: busy — #5 busiest of the park's 12 months. Cooler air arrives; elk rut begins in Cataloochee. The editorial best window here is June & October. You get about 12h 24m of daylight. To finish Alum Cave Trail (2h 5m) before dark, leave the trailhead by about 5:35 PM.
Month data reviewed · how we check this
| Verdict | Good A solid visit with a caveat — usually crowds or heat. |
|---|---|
| Temps °F | 81° high / 57° low |
| Crowds | busy · #5 busiest of the park's 12 months |
| What September is like | Cooler air arrives; elk rut begins in Cataloochee |
| Best window (whole year) | June & October |
| Peak crowds (whole year) | Jun–Aug, Oct |
CROWDS: RELATIVE SEASONALITY FROM NPS VISITATION STATISTICS · TEMPS: APPROXIMATE NOAA NORMALS AT MAIN VISITOR ELEVATION — HIGH COUNTRY RUNS 10–20°F COLDER
DAYLIGHT ON SEPTEMBER 15 · LOCAL PARK TIME (EDT)COMPUTED FROM THE PARK'S OWN COORDINATES FOR THE 15TH — THE MIDDLE OF THE MONTH STANDS FOR IT, AS IT DOES FOR CLIMATE NORMALS. WITHIN A MONTH THESE TIMES SHIFT BY UP TO AN HOUR
LEAVE THE TRAILHEAD BY — TO FINISH BEFORE DARK ON SEPTEMBER 15WALKING TIMES ESTIMATED FROM EACH TRAIL'S MEASURED DISTANCE AND ELEVATION GAIN — A PLANNING FIGURE, NOT A PACE. ADD YOUR OWN MARGIN FOR PHOTOS, REST AND CROWDS. WATER AT THE COOL-WEATHER RATE, BECAUSE THIS MONTH AVERAGES 81°F. TRAILS WE HAVE NOT MEASURED ARE LEFT OUT RATHER THAN GUESSED
WHAT SEPTEMBER ASKS OF YOU HEREGreat Smoky Mountains National Park in October — Best window, highs around 71°F, crowds: peak crowds (foliage peaks mid-to-late october — glorious and packed).
Our verdict for September is "Good". A solid visit with a caveat — usually crowds or heat. Expect highs around 81°F and lows around 57°F, with crowds at the "busy" level. Temperatures are approximate NOAA normals at the main visitor elevation; crowd levels follow published NPS visitation statistics.
Across the full 12-month review, the best window is June & October, and the peak-crowd months are Jun–Aug, Oct. September itself we rate "Good".
October we rate "Best window" against "Good" for September, with highs around 71°F and crowds at the "peak crowds" level.
About 12h 24m on September 15: the sun rises around 7:17 AM and sets around 7:40 PM local park time (EDT). Computed from the park's own coordinates, so it is the light you actually get at the trailhead, not the nearest city's.
Alum Cave Trail takes about 2h 5m of walking, so on September 15 you would need to leave the trailhead by about 5:35 PM to finish before dark — the sun sets around 7:40 PM local park time (EDT). Walking times are estimated from each trail's measured distance and elevation gain, so treat them as a planning figure and add your own margin for photos, rest and crowds.
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