The climate in Vietnam

Climate zone: tropics

High humidity and hot temperatures make the weather in Vietnam pleasant at times but also tropical humid. It is warm to hot all year round, inviting bathing at average water temperatures of 27 degrees. The warmest and at the same time rainiest region is Mekong Delta. The coldest is Northeast. Because of the lower temperatures, the best time for traveling is from December to February. Try to avoid the rainy season from July to October.

Temperature records of the last 74 years

The hottest temperature measured from 1949 to January 2023 was reported by the Hanoi weather station. In June 2017, the record temperature of 42.5 °C was reported here. The hottest summer from July to September, based on all 17 weather stations in Vietnam below 680 meters altitude, was recorded in 2020 with an average temperature of 28.9 °C. This average temperature will normally be measured every four to six hours, thus also including the nights. Normally, this value is 28.0 degrees Celsius. The average maximum daily temperature at that time was 33.2 °C.

The coldest day in these 74 years was reported by the Lang Son weather station. Here the temperature dropped to 0.3 °C in January 2014. Lang Son lies at an altitude of 263 meters above sea level. The coldest winter (January to March) was in 1980 with an average temperature of 15.2 °C. In Vietnam, it is usual to have about 7.0 degrees more at 22.2 °C for this three-month period.

The most precipitation fell in November 2004. With 50.9 mm per day, the Hue weather station recorded the highest monthly average of the last 74 years. Incidentally, the region with the most rainfall for the whole year is around Hue. The driest region is near Phan Thiet.

Long-term development of temperatures from 1998 - 2022

In contrast to single record values, long-term development cannot simply be brought about by all weather stations in the country. Both the number and the locations are constantly changing. An average value would give a distorted result. If several measuring stations in particularly cold mountain or coastal regions are added in one year, the average would decrease as a result of this alone. If a station fails during the summer or winter months, it does not provide any values and distorts the average again. The subsequent long-term development was therefore reduced to only 4 measuring points in order to have comparable data over as long a period as possible.

In the years 1998 to 2022, there were only these 4 weather stations in the whole country, which reported continuous temperature values (Nha Trang, Vinh, Haiphong, Da Nang). From these weather reports, we have created a long-term development that shows the monthly average temperatures. The hottest month in this entire period was June 2019 at 31.1 °C. February 2008 was the coldest month with an average temperature of 17.5 °C.

The average annual temperature was about 25.3 °C in the years after 1998 and about 25.9 °C in the last years before 2022. It has therefore increased only slightly by about 0.6 °C over the past 25 years. This trend only applies to the selected 4 weather stations in Vietnam. A considerably more comprehensive evaluation of global warming has been provided separately.

Data basis and methodology

The data from the individual measuring stations are based on the archives of the German Weather Service, individual values averaged and supplemented by own elements. In order to determine a representative national average, average values were first calculated for each part of the country, which were then summarized at the national level. Thus, if a disproportionate number of weather stations are located in a small area, their number does not affect the national average. There are 18 stations in Vietnam itself. In 4 cases, neighboring but nearby weather stations were also used to obtain more accurate values.