Jangma: Korea's Summer Monsoon Season
What and When Is Jangma?
*Jangma* (장마) is the Korean summer monsoon season, typically running from late June through late July. It is triggered by a clash between cold air masses from the north and warm, humid air from the south, creating a stationary front that parks itself over the Korean peninsula.
Unlike brief summer thunderstorms in other regions, *jangma* means weeks of relentless overcast skies, fog, and persistent rain. It rarely rains continuously at maximum volume the entire time, but dry, sunny days are rare. Instead, weather patterns shift between steady drizzles and sudden, torrential downpours that can drop inches of rain in a single hour.
Daily Life and Practical Struggles
Living through *jangma* means dealing with intense humidity that hovers near 100 percent. Locals rely heavily on dehumidifiers and air conditioners running constantly to keep apartment walls and closets from growing mold. Hanging laundry outside is impossible, so indoor drying racks and coin laundromats with high-powered dryers see heavy traffic.
Walking around cities means navigating a sea of umbrellas. Sidewalks get crowded, and convenience stores sell cheap plastic umbrellas by the thousands. Shoe care is a major preoccupation; waterproof footwear or sandals are essential because canvas sneakers soaked in a monsoon puddle will take days to dry out.
Safety Risks Outdoors
The heavy, sustained rainfall makes outdoor activities hazardous. Mountain hiking trails, particularly around popular spots like Bukhansan or Seoraksan, can quickly become slick, mud-sliding traps. Stream banks and riverside walking paths—such as those along Seoul's Han River—can flood with astonishing speed as upstream reservoirs are released.
City authorities routinely close underpasses, low-lying riverside parking lots, and hiking trails when rainfall surpasses safety thresholds. If you are visiting during this period, pay close attention to emergency alerts on your phone, which broadcast warnings about localized flash floods and landslides.
How to Prepare as a Visitor
If you are traveling to Korea during *jangma*, abandon any plans for a pristine travel wardrobe. Pack quick-drying fabrics, breathable clothes, and at least one pair of reliable waterproof shoes or sandals. Leave leather shoes at home.
Expect outdoor sightseeing plans to be disrupted. Keep a flexible itinerary that swaps out temple visits or hiking for massive indoor options like COEX Mall, the National Museum of Korea, or the endless network of underground shopping centers connected to subway stations. On the bright side, indoor cafes are cozy spots to sit out a heavy downpour while watching the gray city through fogged-up glass.
Common questions
Does it rain every single day during jangma?
Not necessarily all day, but you can expect some level of precipitation, heavy cloud cover, or extreme humidity almost daily. Clear, sunny days are the exception during this four-week window.
Are public transport services disrupted by the monsoon?
Subways and buses generally run normally, but sudden flash floods can temporarily close specific underground stations, bus routes, or low-lying road tunnels. Check local navigation apps like Naver or Kakao Map for real-time alerts.