Heavy Rains And Cold Fronts Sweep Vietnam And Korea

As the calendar pages turn toward late October, both Vietnam and South Korea are bracing for a dramatic shift in weather, with forecasters warning of heavy rainfall, plummeting temperatures, and a heightened risk of severe storms. According to the National Hydrometeorological Forecast Center in Vietnam and the Korea Meteorological Administration, the coming days will test infrastructure, resilience, and even daily routines across both countries.

Starting October 18, 2025, Vietnam's northern and central regions are expected to receive between 70 and 150 mm of rain, with isolated areas possibly enduring deluges of over 300 mm. The risk is especially acute for flash floods, as rainfall rates could exceed 80 mm within just three hours. The center's warning system has flagged a Level 1 natural disaster risk due to the combined threats of heavy rain, tornadoes, lightning, hail, and strong winds. "Thunderstorms, hail, strong winds, and tornadoes are expected in some areas," the forecast notes, underscoring the need for vigilance.

On the same day, Vietnam's central and southern regions will also experience showers and thunderstorms, with rainfall amounts ranging from 10 to 30 mm and, in some pockets, up to 60 mm. The afternoon and evening hours are expected to be the most active, with weather events potentially intensifying into severe storms. The forecast is clear: "Thunderstorms, hail, and strong winds are likely in northern and central mountainous areas," reports VietnamNet, reflecting the widespread nature of the threat.

Hanoi, Vietnam's bustling capital, will see a high of 31 to 33 degrees Celsius on October 18, but conditions will shift rapidly. The forecast calls for scattered showers and thunderstorms in the evening and night, with the mercury dipping to lows of 23 to 25 degrees. By October 19, the city will feel the first bite of incoming cold air, with temperatures dropping to 19 to 21 degrees Celsius by evening. This cold snap isn't limited to the capital—mountainous regions could see temperatures as low as 16 degrees Celsius, a stark contrast to the recent warmth.

From October 20 to 22, the cold front will strengthen, extending its reach into Vietnam's north-central and central regions. Meteorologists warn that frost and cold damage are possible, especially in higher elevations, where the chill will be felt most acutely. For the broader region, this means lows of 17 to 19 degrees Celsius in the mountains and even colder in the highlands. "From the evening of October 19, 2025 to the morning of October 20, 2025, cold air will continue to affect the northern regions," the forecast continues, highlighting the persistence of the cooling trend.

Elsewhere in Vietnam, weather conditions will be equally dynamic. The northwest and northeast are set for cloudy, sunny spells, but evening and nighttime storms remain a concern. Central highlands and southern provinces, including Ho Chi Minh City, will also contend with scattered showers and thunderstorms, with the possibility of localized heavy downpours. Notably, the risk of tornadoes, lightning, and strong gusts remains elevated, particularly during stormy periods. "Breezes will be light, but thunderstorms can bring tornadoes, lightning, and strong winds," the National Hydrometeorological Forecast Center cautions.

Turning to South Korea, the Korea Meteorological Administration paints a similarly turbulent picture. On October 18, heavy rain is forecast for most of the country through noon, with the southern coast and Jeju Island likely to see precipitation continue into the afternoon. Winds will be a major hazard, with gusts reaching 55 km/h in many regions and up to 70 km/h in areas under a strong wind advisory. "Strong winds of about 55 km/h are forecasted in northern and central regions in the morning, increasing to about 70 km/h in some areas," BNT News reports, urging residents to secure property and remain alert for safety hazards.

Despite the blustery and wet start, air quality remains a bright spot, with fine dust concentrations expected to stay at 'good' levels nationwide. Temperature-wise, October 18 will see highs of 19 to 24 degrees Celsius across major cities, with Seoul and Incheon peaking at 19 degrees, and Busan and Jeju slightly warmer.

Sunday, October 19, brings further changes. Rain will persist in Gangwon and Jeju regions through the morning, but most of the country will transition from cloudy to clearer skies by afternoon. However, a new challenge emerges: the arrival of cold air from the north. Morning lows will dip to between 5 and 14 degrees Celsius, with daytime highs only reaching 19 to 23 degrees. The Korea Meteorological Administration warns, "From the evening of October 18, 2025 to the morning of October 19, 2025, cold air will affect northern regions with temperatures dropping." The wind will amplify the chill, making it feel even colder—an abrupt reminder that autumn is giving way to winter.

As the week progresses, the cold snap will deepen. On Monday, October 20, central and northern regions will see further cooling, with morning lows in Seoul expected to plummet to just 6 degrees Celsius. By Tuesday, October 21, cold air will persist in Gangwon and Jeju, with temperatures ranging from 3 to 22 degrees Celsius. The forecast for October 22 to 24 calls for continued strong winds and heavy rain, especially in the northern and central regions. "The coldest temperatures on October 20, 2025 will range from 3 to 15 degrees Celsius in Seoul and surrounding areas," BNT News adds, noting the need for extra care amid the abrupt temperature shifts.

Looking further ahead, the pattern of unsettled weather continues. From October 22 through 25, cloud cover will dominate, particularly in Gangwon, which will also see frequent rain. Morning lows will hover between 4 and 15 degrees Celsius, while daytime highs will remain in the 15 to 23 degree range. The sea will also be rough, with waves reaching up to 4 meters in key coastal waters—a warning to mariners and coastal communities alike.

Both Vietnam and South Korea are thus entering a period marked by volatility: heavy rains that can trigger floods and landslides, strong winds capable of damaging infrastructure, and a sudden drop in temperatures that could catch the unprepared off guard. Authorities in both countries are urging citizens to monitor forecasts closely, secure loose objects, and take precautions against the hazards posed by storms, cold, and flooding. In the words of the Korea Meteorological Administration, "Rapid temperature changes require careful health management." Meanwhile, Vietnam's meteorologists stress the importance of readiness for all manner of severe weather—be it rain, wind, or the creeping cold.

As the region faces the twin challenges of storm and chill, the coming days will demand vigilance, adaptability, and, perhaps above all, a healthy respect for the power of the elements.