July 21 Heavy Rainfall in the Seoul Metropolitan Area: Rush-Hour Timing and Regional Safety Precautions

이 포스팅은 쿠팡 파트너스 활동의 일환으로, 이에 따른 일정액의 수수료를 제공받습니다.

This article is based on the latest available news reports and official information as of 2026-07-21 Korea Standard Time.

As of 2026-07-21 4:12 a.m., heavy rainfall may coincide with the morning commute across the Seoul metropolitan area.

Rain could become particularly intense in Incheon and northern Gyeonggi Province from early morning through the morning hours, and in Seoul and southern Gyeonggi Province after 6 a.m. Rather than simply bringing an umbrella, commuters should also check their routes and departure times.

When Is the Rain Expected to Be Heaviest?

According to the forecast issued by the Korea Meteorological Administration (KMA) on the night of 20, heavy rainfall may be concentrated in Incheon and northern Gyeonggi Province between 3 a.m. and 9 a.m.

The most intense rainfall is expected from the late predawn hours into the morning, with some locations potentially receiving 50~80 mm of rain per hour.

Seoul, southern Gyeonggi Province, and the 5 islands in the West Sea are forecast to receive approximately 30~50 mm of rain per hour between 6 a.m. and 9 a.m. Heavy rainfall may also continue through the morning in inland areas of northern Gangwon Province.

The forecast can be divided into the following periods for morning commuters:

3~6 a.m.: Rainfall may intensify rapidly, particularly in Incheon and northern Gyeonggi Province.

6~9 a.m.: The period when commuter traffic and public transportation demand are concentrated across the Seoul metropolitan area.

9~12 a.m.: Rainfall may intensify again even after temporarily weakening.

Today, deciding whether to change your route may matter more than the size of your umbrella.

Areas Under a Preliminary Heavy Rain Advisory as of 3:40 a.m.

The preliminary heavy rain advisory announced by the Korea Meteorological Administration at 3:40 a.m. included the following areas.

In Seoul, the southeastern and northeastern districts were included. In Incheon, Ongjin and Yeongjong were designated.

In Gyeonggi Province, the advisory included Gwangmyeong, Gwacheon, Ansan, Siheung, Gapyeong, Suwon, Seongnam, Anyang, Guri, Namyangju, Gunpo, Uiwang, Hanam, Hwaseong, Gwangju, parts of Yongin, and western Yangpyeong.

In Gangwon Province, Hwacheon and Chuncheon were included, while Taean, Dangjin, and Seosan were designated in South Chungcheong Province.

A preliminary heavy rain advisory is issued to indicate the possibility of severe weather before an official advisory or warning takes effect. The affected areas and effective times may change depending on the movement of rain clouds, so check the latest weather alerts immediately before departure.

Even if your area is not listed, it is too early to assume conditions are safe. When rain clouds develop over a small area within a short period, rainfall amounts can vary significantly even within the same city or county.

Avoid Low-Lying Areas During Your Morning Commute

This morning, choosing a route with a lower risk of flooding is more important than simply finding the least congested road.

If your usual route includes an underpass, a road alongside a river, a passage beneath railway tracks, or a low-lying intersection, it is safer to identify an alternative route in advance.

If water has accumulated on the road, do not automatically follow another vehicle simply because it managed to pass through. Vehicles have different ground clearances, water depths may vary, and submerged manholes or damaged road surfaces may be impossible to see.

As a general rule, do not enter even a slightly flooded underpass or road. Do not attempt to judge the water depth yourself.

Bus and subway passengers should also check service announcements and arrival information before leaving home. This does not mean that all routes are currently experiencing disruptions, but concentrated heavy rainfall can cause road congestion and delays in public transportation services.

Driving? Check These Things First

If driving is essential, it is advisable to check rainfall conditions again, particularly during 6~9 a.m.

Before departure, identify underpasses and riverside sections along your route, and plan alternative routes using major roads where possible.

If heavy rain reduces visibility while driving, slow down and increase the distance between your vehicle and the one ahead. Rather than continuing to drive with your hazard lights flashing, first consider whether you can safely pull over and stop temporarily.

If water enters your vehicle or the engine stalls, avoid repeatedly attempting to restart it. If floodwater is rising rapidly, prioritize evacuating people over protecting the vehicle.

5-Minute Checklist Before Leaving Home

In apartments and houses, check that water can drain properly around windows and through balcony drains. If leaves or household items are blocking drainage outlets, clear them where it is safe and practical to do so.

For semi-basement homes, underground parking garages, and buildings in low-lying areas, check the conditions around entrances and locate accessible emergency stairways before floodwater begins entering the building, rather than waiting until flooding starts.

Avoid riverside walking paths, valleys, and areas near mountain slopes even if the rain temporarily weakens. When the ground is already saturated from earlier rainfall, soil erosion or falling rocks can occur even after the rain stops.

If someone in your family leaves early for work or school, it is useful to share these three things:

An alternative route that avoids the underpass normally used.

A designated meeting place if you cannot contact one another.

The specific area name to check immediately upon receiving an emergency alert.

What to Check This Morning, in Order

First, check the Korea Meteorological Administration's weather radar and alerts rather than relying solely on the rain currently falling outside. Even if rainfall is light near your home, intense rain clouds may be passing over your destination or the areas along your route.

Second, check road conditions and public transportation services. Leaving 10~20 minutes earlier than usual is one option, but if heavy rainfall is concentrated during that period, adjusting your departure time may be better than rushing.

Third, check announcements from your workplace or school. Remote work arrangements, changes to school start times, and event cancellations vary by institution, so official notices should be consulted.

The most important periods to watch in this forecast are the predawn and morning hours in Incheon and northern Gyeonggi Province, and the morning commute in Seoul and southern Gyeonggi Province.

Rainfall areas and weather advisories may continue to change. Immediately before leaving, check the weather not only at your home but also at your destination and along your travel route.

이 포스팅은 쿠팡 파트너스 활동의 일환으로, 이에 따른 일정액의 수수료를 제공받습니다.