The National Center for Hydro-Meteorological Forecasting has forecast the weather trend for the seasonal season (from May - October 2026). Among them, one of the notable information is the forecast of hot sun and rainy season this year.
Hot weather more intense than the same period
Regarding the temperature trend, from October to October, the average temperature nationwide is generally 0.5-1.5 degrees Celsius higher than the multi-year average of the same period.
According to Mr. Nguyen Van Huong - Head of Weather Forecast Department, National Center for Hydro-Meteorological Forecasting, from May, hot weather will continue to occur and increase in intensity in the Northern and Central regions. Especially for the Central and Southern highlands, hot weather is likely to gradually decrease from around the end of May 2026.
This year, hot weather is forecast to be more frequent and intense than the average. The number of hot days is likely to occur more than the multi-year average and compared to the same period in 2025" - Mr. Huong said.
In August - September, hot weather will continue to occur in the Northern and Central regions. From about the beginning of September, hot weather will gradually decrease in the Northern region and from the second half of September it will decrease in the Central region.
Mr. Huong recommends that there may still be unusually late heat waves.
Overall, extreme heat is no longer a strange phenomenon but is becoming an increasingly clear characteristic in the context of climate change and ENSO shifting to a hot phase" - Mr. Huong said.
Rain may be less, but the risk of increasing extreme rain frequency
According to the meteorological agency, regarding the rainfall trend, in May, the total rainfall nationwide is approximately equal to the multi-year average. In June, the total rainfall in the Northwest, the Northern Delta, and provinces from Thanh Hoa to Hue are generally 5-20% higher than the multi-year average, the remaining areas are generally approximately equal to the multi-year average of the same period. In July, the total rainfall is generally 5-10% higher than the multi-year average, especially in the South Central Coast region, the total rainfall is generally approximately equal to the average.
In August, the total rainfall is generally approximately equal to the multi-year average. In September, the total rainfall is generally 5-20% lower; especially in the Central Highlands and Southern regions, it is generally approximately equal to the multi-year average. In October, the total rainfall is generally 5-20% lower than the average, especially in the Northern region, it is approximately the same period.
The southwest monsoon in the south is likely to operate from about the second half of May, causing increased showers and thunderstorms in the Central Highlands and Southern regions. Therefore, the rainy season in the Central Highlands and Southern regions appears later than the average of many years.
According to multi-year average data, the rainy season in the Central Highlands region is around the last week of April, the first week of May; in the Southern region it is around the first half of May.
According to Mr. Huong, the rainy season in the North is approximately average, around May 2026; in the Central region around September. Moderate and heavy rains are likely to appear in the above area during the forecast period.
Rain tends to be less, however, it is noteworthy that the distribution of rain tends to be more extreme. The number of widespread heavy rains may be approximately or lower than the average, but localized heavy rains with very high intensity in a short period of time tend to increase" - Mr. Huong recommended.
According to the Head of the Weather Forecast Department, widespread heavy rains are likely to start from June 2026 in the North, then gradually spread to the South and end around November 2026 in the Central provinces. The risk of flash floods and landslides in the Northern and Central mountainous areas may increase, especially during the peak months of the rainy season and transitional periods.
