According to Le Manh Dung, a forecaster with the Southern Regional Hydro-Meteorological Center, El Niño continued to intensify sharply in August and is forecast to strengthen further in September 2026.

Under the influence of El Niño, average temperatures across southern Vietnam in September are forecast to be 1-2°C above the long-term average.

Daytime highs will generally range from 31-34°C, with some days reaching 35-36°C. The lowest temperatures are expected to range from 25-28°C.

Dong Nai and Ca Mau are forecast to record the largest temperature increases compared with the overall regional average.

In Ho Chi Minh City, average temperatures in September are expected to be around 1-1.5°C above the long-term average. The northwestern part of the city is forecast to be notably hotter, with temperatures 1.5-2°C above normal.

Rainfall declines, strong winds pose risks at sea

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Despite being in the rainy season, Ho Chi Minh City and southern Vietnam could still experience periods of intense heat in September. Photo: Hue Ex

Alongside rising temperatures, total rainfall across southern Vietnam in September is expected to be below the long-term average.

In Dong Nai and Ca Mau, rainfall is forecast to fall short of normal levels by around 50-70 millimeters, equivalent to a decline of 10-20%.

In Ho Chi Minh City, the rainfall deficit is generally expected to range from 10-50 millimeters. The city center and northern areas are likely to see the greatest shortfalls, at around 60-80 millimeters, or 5-25% below the long-term average.

Despite the overall decline in rainfall, widespread heavy rain could still occur during the first 15 days of September.

The meteorological agency also warned vessels operating in southern waters during the first half of September to be alert to risks from a strong southwest monsoon.

With rainfall declining and temperatures rising, the regional meteorological agency has advised local authorities and residents to proactively store fresh water. The measure is intended to help meet household, industrial and agricultural irrigation needs and reduce the risk of localized water shortages in the coming period.

Bao Anh