South Korea's busiest travel periods include spring cherry-blossom season in late March and April, autumn foliage in October and November, and major public holidays such as Seollal (Lunar New Year) and Chuseok (autumn harvest festival). Dates for the lunar holidays change each year, and transport can be heavily booked as residents travel domestically. July and August bring summer holidays, while ski resorts peak in winter. Late May, early June and parts of September can be less crowded, outside public holidays and major festivals.

South Korea's main seasonal weather hazards are summer monsoon rain and typhoons, typically from June to September, with heavy rainfall sometimes causing flooding and landslides. Typhoons can disrupt flights, ferries and coastal activities, particularly in August and September. Winter brings cold snaps, snow and icy conditions, especially inland and in mountainous areas. Earthquakes occur but are less frequent and generally less prominent in travel planning than in Japan. Spring dust and fine-particle pollution can also affect air quality. Check weather and air-quality alerts during seasonal extremes.

South Korea has four distinct seasons. April to May brings mild spring weather and blossoms, while June to August is hot, humid and affected by the summer monsoon, with the heaviest rain often in July. September and October are generally pleasant, with cooler air and autumn foliage. December to February is cold, with snow and icy conditions possible, particularly inland and in mountain areas. Spring and autumn are often the most comfortable seasons for city sightseeing, but they also attract more visitors. Weather can vary between Seoul, the southern coast and mountain regions.