The first thing to keep in mind about Smokies weather: Elevations in the park range from 875 feet all the way up to 6,643, so temps can vary 20-plus degrees from the bottom to the top. As can rainfall—on Clingmans Dome, around 85 inches of rain come down per year, but the lowlands see only 55.
If you come in summer, be prepared for humidity and haze, with afternoons bringing thunderstorms everywhere and 90-degree heat down low (at the summits, it never goes above 80).
Fall brings warm days, cooler nights, less rainfall, and clearer air, with frosts hitting the higher elevations by the end of September. Want foliage? Leaves can start turning in mid-September, and the colors roll downhill until November.
Winters aren’t usually extreme (snow in January and February, plenty of days in the 50s), but both 70-degree and minus-20-degree days have been recorded.
Spring is highly variable—it can snow, and it can reach 80. Because of the park’s popularity, the roads can get jammed, especially in June and July, when kids are out of school, and any time the leaves are changing. Your best bet? Come during weekdays and try to hike or backpack several miles away from the parking lots—or skip the high season and enjoy the park at a quieter, possibly colder, possibly wetter time.