Photo credit: korea.net
Korea.net has their 'fall color predictions' in for the top dozen or so mountains in Korea. Though the mountains are far from the only places you'll see the leaves changing colors, they are where people take special trips to enjoy the scenery. Expect the foliage to start changing as soon as the 3rd and as late as the 30th (the further south you go, the later the change starts, roughly speaking). By now, people in Korea have already noticed a bit of chill in the air - it's almost as though the heat switch got turned off right after Chuseok.