Why is the weather in northern Vietnam still as cool as late spring in late May?

In May 2024, northern Vietnam experienced many days of thunderstorms, with the weather being as cool as the end of spring, with the highest temperature not exceeding 32 degrees Celsius.

After a severe heat wave in late April, Hanoi and other provinces in northern Vietnam experienced the beginning of summer with consecutive days of thunderstorms, some places experiencing heavy to very heavy rain. For many days, the highest temperature did not exceed 32 degrees Celsius, and the weather was pleasant and cool like late spring. At night, the lowest temperature dropped to only 23 degrees Celsius in some places.

This weather pattern has surprised many because previously, the meteorological agency predicted that in May, the low-pressure area in the west would be active, which would result in many days of hot and extremely hot weather in the northern region and the provinces from Thanh Hoa to Phu Yen, with some places experiencing particularly severe heat.

Although it has been almost 20 days since the beginning of summer, the weather in northern Vietnam these days is still cool. (Illustration: Minh Duc)

In response to PV, Assoc. Prof. Dr. Phan Van Tan from the Faculty of Meteorology, Hydrology, and Oceanography, University of Natural Sciences, Vietnam National University, Hanoi, said that the weather in May this year is similar to the beginning of summer in 2022. The rain is considered one of the reasons why the weather in Hanoi and the northern provinces has remained cool for many days.

"The recent rain is due to a combination of weather patterns, mainly the intrusion of cold air from the north, the activity of the Meiyu front cloud band in the north, and the tropical convergence zone, which is moving northward in the central region," said Assoc. Prof. Dr. Phan Van Tan.

Explaining the cool weather in the north in recent days, a representative of the Hai Phong Hydro-Meteorological Station said that in May of this year, cold air has been more frequent.

"Northern and central Vietnam have experienced a widespread heat wave, with many places reaching over 40 degrees Celsius. However, May of this year is different because cold air has been more frequent than in previous years, causing rain and a decrease in temperature," said a representative of the Hai Phong Hydro-Meteorological Station.

A meteorological expert from the National Center for Hydro-Meteorological Forecasting said that this is the transitional season, and there are still cold waves affecting the weather, causing rain and cool temperatures.

"In June and July, when the real summer arrives, there will be more hot and sunny days," the expert said.

According to statistics from the National Center for Hydro-Meteorological Forecasting, in May, hot weather only persisted in the central and south-central regions on May 1-2. On May 3, the hot weather narrowed down to only occur in some areas.

Meanwhile, from May 1-13, the northern region experienced continuous thunderstorms, with some days having moderate to heavy rain. On May 4, 7, and 11, there was intermittent rain. In the first half of the month, the total rainfall in this region was 100-200% higher than the multi-year average for the same period, with some places exceeding 200%.

On May 2-4, May 6-7, and May 10-13, thunderstorms expanded to the area from Thanh Hoa to Thua Thien Hue. In the Central Highlands, there was scattered rain and thunderstorms from May 2-5, with some places experiencing moderate to heavy rain. In the southern region, there were scattered showers and thunderstorms on May 4-5, May 7-9, May 11, and May 13.

From now until the end of May, hot weather will be less intense throughout the country. Thunderstorms in the north will continue, with some areas experiencing heavy to very heavy rain from the night of May 27-31.

According to the forecast, in June, hot and extremely hot weather is likely to return to the northern and central regions. In the south, the southwest monsoon is expected to become more active, so rainfall may increase in the Central Highlands and the southern region.

In addition, the meteorological agency said that from now until the end of June 2024, El Nino is expected to transition to a neutral state with a probability of 80-85%. From July to August 2024, ENSO will gradually transition to a La Nina state, with a probability of 65-75%.

From now until August 2024, there may be 3-5 typhoons or tropical depressions in the East Sea, of which about 1 will make landfall. The entire country should continue to be on guard against dangerous weather phenomena such as thunderstorms, tornadoes, lightning, hail, and strong gusts of wind.

Summary

The weather in northern Vietnam has been unseasonably cool in late May due to a combination of factors, including frequent cold air intrusions, the Meiyu front cloud band, and the tropical convergence zone. As a result, temperatures have remained below 32 degrees Celsius, and there have been widespread thunderstorms. This pattern is expected to continue until the end of the month, with the possibility of heavy to very heavy rain from the night of May 27-31. However, in June, hot and extremely hot weather is likely to return to the northern and central regions.