According to Nguyen Van Huong, head of weather forecasting at the National Centre for Hydro-Meteorological Forecasting, the September 28–October 2 heatwave was unusually late for northern Vietnam.
Weather stations across the region recorded exceptionally high temperatures. In September, 13 stations matched or exceeded historical highs for the same period, rising to 42 out of 88 stations in October.
Huong attributed the unusual heat primarily to a very strong El Nino, with sea surface temperatures in the Nino 3.4 region reaching 2.1 degrees Celsius above average in September and 2.4 degrees in mid-October.
During particularly strong El Nino events, monthly average temperatures from autumn through the following summer can exceed normal levels by 1–2 degrees Celsius, he said.
A strong subtropical high-pressure system covering northern Vietnam also intensified sunshine and pushed temperatures further above seasonal averages.
Nguyen Van Huong, head of weather forecasting at the National Centre for Hydro-Meteorological Forecasting, describes October's heat in northern Vietnam as unusual.
The prolonged warmth could disrupt agricultural production, particularly crops requiring cooler temperatures for growth and flower development. It may also alter planting schedules and patterns of pest outbreaks.
Huong forecast widespread heavy rain in central Vietnam through October 29, with 60–130 mm expected from Ha Tinh to Danang and over 250 mm in some areas.
No significant cold air outbreak was expected in northern Vietnam before the end of October, although a cold spell could arrive in the first half of November, bringing rain and cooler conditions.
He urged residents to heed official weather warnings and farmers to adapt to changing conditions, stressing early prevention over disaster response.
October brought northern Vietnam its first region-wide heatwave for the month since 1991.