Northern Vietnam to See First Seasonal Cold Air and Storms from September 9

Northern Vietnam is expected to receive its first weak seasonal cold air from around September 9, bringing scattered showers and thunderstorms. The National Center for Hydro-Meteorological Forecasting said the change could become apparent from the night of September 9 to 10.

Temperatures in the northern region are forecast to drop clearly on September 10 and 11. Daytime temperatures will generally range from 28 to 31°C. Overnight and early-morning temperatures are expected to fall to 23 to 26°C in the plains and 21 to 23°C in mountainous areas.

Hanoi could see showers and thunderstorms, with daytime temperatures no higher than 31°C and overnight temperatures of 24 to 25°C. In the high mountains, Sa Pa in Lao Cai province is forecast to receive rain, with daytime temperatures of 21 to 22°C and nighttime temperatures falling to 17 to 18°C.

Before the cold air arrives, northern Vietnam will have sunny days from September 7 to 9, with highs below 35°C. Showers and thunderstorms could occur in some places in the late afternoon and at night. Central Vietnam is expected to see more rain between September 10 and 15 as the intertropical convergence zone forms and combines with the seasonal cold air. Areas from Thanh Hoa to Da Nang, along with eastern parts of Quang Ngai and Gia Lai, could receive moderate rain and locally heavy to very heavy downpours.

The Central Highlands and southern Vietnam may also see stronger southwest monsoon activity from September 10 to 12, bringing moderate rain, thunderstorms, and locally very heavy rainfall. Meteorologists noted that low-pressure vortices already exist along the convergence zone over the central South China Sea. They could develop into a tropical depression, causing strong winds, high waves, and severe thunderstorms at sea. Heat in central Vietnam is expected to gradually ease in September, while cold air from September through November 2026 is forecast to be weaker than average. Severe cold could arrive later than usual between December 2026 and January 2027.