Rain Arrives in Stages on Sunday

South Korea is expected to see a mix of clouds and sunshine on Sunday, October 4, as autumn rain moves across the country in stages. Showers are forecast first on Jeju Island and along parts of the southeastern coast, with rain reaching the Seoul metropolitan area and other central locations later in the day.

The rain is linked to a weather trough moving east from the Yellow Sea. A trough is an elongated zone of low pressure that can encourage clouds and showers to form; in everyday terms, it acts like a passing weather disturbance that brings unsettled conditions as it travels.

The main change to watch is timing: southern and southeastern areas may get rain during the day, while parts of central South Korea are expected to turn wet after dark.

Where and When Rain Is Expected

Jeju may see showers through the morning, with the forecast total below 5 millimeters. Busan, Ulsan and the eastern coast of North Gyeongsang Province are expected to receive 5 to 10 millimeters of rain between morning and afternoon.

Rain is forecast to begin at night in the Seoul metropolitan area, northern inland parts of Gangwon Province, South Chungcheong Province and the northwestern part of North Jeolla Province. The exact start time may vary from place to place, so people planning evening travel or outdoor activities should check local forecasts before heading out.

  • Morning to afternoon: Showers are possible on Jeju and along the southeastern coast.
  • Sunday night: Rain may begin in the Seoul region and several other central and western inland areas.
  • Monday, October 5: Showers could spread more widely across central and southern parts of the country.

Showers May Continue into Monday

From early Monday through the morning, rain is expected to extend across central South Korea and the Jeolla region. It may also reach the northwestern inland areas of North Gyeongsang Province, western inland areas of South Gyeongsang Province and Jeju.

Rainfall can be uneven during this kind of passing weather system. One neighborhood may get a brief shower while another nearby area stays mostly dry, much like the difference between walking through a short-lived shower and missing it by a few streets.

The forecast does not provide rainfall totals for all of the areas expected to get wet on Monday. Residents should therefore use updated local forecasts for details, particularly if they have outdoor plans, road travel or work that depends on dry conditions.

Thunder, Gusts and Small Hail Are Possible

Some areas receiving rain could also experience sudden strong gusts and thunderstorms. Thunderstorms may bring a quick change in conditions, including heavier bursts of rain and reduced visibility for drivers.

Small hail is also possible along the central west coast, in northern inland parts of Gyeonggi Province and in northern inland Gangwon Province. Small hail consists of little pellets of ice; although it is generally smaller than the hailstones associated with severe storms, it can still damage crops or delicate outdoor equipment.

People in areas where small hail is possible should take precautions with crops and vulnerable property, such as moving potted plants or covering sensitive equipment when practical.

Mild Afternoon Temperatures

Afternoon highs are forecast to range from 22°C to 26°C, close to or slightly above typical levels for this time of year. Expected highs include 24°C in Seoul, Incheon, Chuncheon, Chungju and Busan; 23°C in Gangneung; 25°C in Daejeon, Jeonju and Daegu; and 26°C in Gwangju. Jeju is expected to reach about 24°C.

These temperatures may feel mild during the afternoon, but conditions can feel cooler when rain and wind arrive. A light waterproof layer can be useful for people who will be outdoors later in the day, especially in areas where showers are forecast to begin at night.

Dry Conditions in Seoul Raise Fire Concerns

Despite the approaching rain, Seoul remains under a dry-weather advisory, and the air there is very dry. Winds are also expected to be somewhat strong, allowing a small spark to spread more easily than it might in damp conditions.

Residents should take care with activities that can produce sparks or open flames. This includes avoiding careless disposal of cigarettes and being especially cautious around dry grass, wooded areas and other places where a fire could spread quickly.

The arrival of rain later does not remove the risk everywhere or immediately. Until showers reach a particular location, dry vegetation and gusty winds can still contribute to dangerous fire conditions.

Air Quality Forecast to Be Good

Fine-dust levels are forecast to remain good in every region. That means air pollution is not expected to be a major concern in the national forecast, although local conditions can always differ.

For Sunday, the key practical points are the changing rain timeline, possible thunderstorms and small hail in a few areas, and continued fire caution in dry parts of Seoul. Rain is expected to become more widespread by Monday morning, so checking updated local forecasts can help people plan travel and outdoor activities.