With four distinct seasons, including a very cold winter, it is best to visit Seoul in autumn, at some time from September to November. The skies are blue and clear, it is sunny and the foliage looks beautiful! Winters are very cold and dry, but are good if you like skiing or below freezing weather, and of course lesser crowds of tourists. Spring from April to May is simply beautiful but the city is flooded with Japanese tourists and it is very hard to get good accommodation during this season. Summers are a definite no as it gets very hot and humid, and typhoon prone as well, and most importantly, expensive!