As being characterized by tropical climate, Northern Vietnam has four distinct seasons: spring, summer, fall, and winter. The weather in summer is hot, humid, and rainy. The temperature may mount to 370C in the peaks of June and July. In the winter, the temperature falls, especially in December and January. Vietnam weather in the north is colder than other same-longitude regions in South East Asia during the winter. The central region is surrounded by mountain ranges stretching from the west to the east. For this position, the climate here is harsher than that in Northern Vietnam and Southern Vietnam. Meanwhile, weather in Southern Vietnam is distinguished by tropical equatorial climate with high temperatures and virtually remains change all year round. The seasonal differentiation is relatively profound and consistent with the operation of the southwest monsoon. The diurnal temperature range between months is low and moderate all year round. The annual humidity ranges from 80% to 82%.
From December to March, this is the winter days in the North of Vietnam. The average temperature can decrease as low as 10 degree. However, the coldness in Northern Vietnam is more severe than that in countries having snow in winters. Coming to Vietnam during the time, remember to bring warm clothes and check the weather forecast before departing, interestingly, moving southward the weather in Vietnam becomes warmer and drier. In December, in Northwestern area such as Sapa, snowfall sometimes comes, and it might be colder than expected. The South of Vietnam witnesses a warmer weather. In Central Vietnam, during the months, the rainy season will end with temperature ranging from 16 to 21 Celsius degree. In the South of Vietnam, the dry season is in its middle period with temperature ranging from 260C to 290C. This time is an ideal months to visit Ho Chi Minh City and the Southern provinces.
From April to July, Vietnam climate sees a hot, humid and rainy summer. The rainfall during these months is more than that of previous months. During the time, weather in Northern Vietnam is in the middle of hot and rainy season. The temperature has yet to rise in the North from 240C to 300C, even higher, especially in June. Meanwhile, the temperature remains constant in the Central and the Southern Vietnam from 250C to 330C. In May, the weather is not too overheated. All parts of Vietnam witness a humid weather during these months. In June and July, the temperature is high across the country. During these months, Southern Vietnam is in hot and rainy season.
In August and September, there are more downpours, thunders and lightning in Vietnam. The months are also rainy months Northern Vietnam. The temperature fluctuates between 280C and 330C in Hanoi and slightly lower in southward provinces. Areas in Central Highlands have a cool and rainy weather. The temperature can fall to below 200C at night. In October, is said to be the best time to visit Vietnam. The Northern weather is typical for autumn. Temperature is moderate with dry air. The weather in Central Vietnam such as weather in Hue, Da Nang and Hoi An sees a rainy season, but the beauty of this region remains. Drizzle weather in Hue has becomes a great inspiration for many generations of Vietnamese poets and artists. In the South, the temperature remains steady, ranging from 240C to 310C with significantly less rain compared with previous summer months. From October to November, almost areas in Northern Vietnam get cooler while those in Central and Southern Vietnam are still in warm and dry air.
Vietnam weather by month is also affected by the movement of monsoons. From October to April, North of Vietnam is dominated by northeast monsoon with light rain, and high humidity. Meanwhile, from May to September, it is the “working time” of south monsoon, causing more rains. From September to January, areas of Central Coastal and Highlands see a great amount of rainfall with typhoons. In south of Vietnam, the weather is sunny and dry during the north monsoon.