Peak Season: July to August
Expect monsoons, high-humidity, and throngs of tourists during Seoul's peak travel season.
Off Season: January to April
Except for the Lunar New Year holiday (a week that falls somewhere between mid-January and early February), this is the best season for hotel discounts. Winter is cold but beautiful with the snow. In March and April, the city transforms into a garden but is also plagued by periodic dust storms.
Shoulder Season: May to June; September to December
In addition to generally pleasant weather, fewer crowds, and some hotel bargains, spring and fall are the most beautiful times of year in Seoul.