Vietnam is located in Southeast Asia, affected by tropical moonsoon.The climate of Vietnam varies considerably from region to region. Although the entire country lies in the tropics and subtropics, local conditions vary from frosty winters in the far northern hills to year-round, subequatorial warmth in the Mekong Delta.
Northern Vietnam (Hanoi, Ha Long Bay, Hai Phong) has two distinct seasons – hot and rainy summers and cool and dry winters. Summer: May – October. Average temperature 24 – 33º C It is hot and humid, especially inland, which is not touched by cool coastal breezes. Tropical rain showers and the occasional typhoon are also possibilities – light clothes and an umbrella are recommended. Winter: November – April. Average temperature 16 – 23º C It remains fairly dry up until late February/March.Best time to visit: During winter when rainfall is minimal and temperatures are comfortable.

Central Vietnam (Hue, Da Nang, Hoi An, Nha Trang) coastal areas are more temperate than the sticky south (although they do experience high rainfall), while the Central Highlands (Da Lat) are pleasantly cooler. Summer: May – October. Average temperature 23 – 24ºC Lowlands (Hue, Da Nang, Hoi An, Nha Trang) The weather is warm and reasonably dry from May to September. The monsoon winds then change bringing above average rain during late September. This time is not very pleasant as it can rain constantly – there is a high probability of flooding, visibility is poor and typhoons are also a possibility. Winter: November – April. Average temperature 17 – 23º C Best time to visit: During the winter between February and April, when rainfall is low and temperatures are warm.

Highlands (Dalat) Temperatures can fall slightly below the average and rainfall is higher than at lower elevations. However,  most rain tends to fall during the summer months when it can be very wet – although these summer months do provide a respite from the often intense heat of other areas. Light cotton clothes are required, although a few warm layers are necessary throughout the year as temperatures can drop away, especially at night. Waterproofs are also a good idea as rain can fall at anytime of the year.

Best time to visit: winter days are pleasantly warm and rainfall is lower from November to March – nights can be chilly. Southern Vietnam (Ho Chi Minh, Bin Thuen, Mekong Delta) is fairly consistently hot and humid all year round. Worth Carrying lightweight jumper as it can be chillingly cold inside air-conditioned buildings during summer.

Summer: May – November. Average temperature 24 – 31º C It is hot, humid and rainy but heavy downpours are usually short lived. Winter: December – April. Average temperature 22 – 33º C Remains hot and humid, although humidity levels are more bearable between December and February. During April and May the southwest monsoon winds bring rain showers to the Mekong Delta and southern Vietnam. Best time to visit: Temperatures are not as extreme from September to February as they can be during March and April when the heat is fierce.
So, Please take Charming Indochina Travel’s advise as : The North The best time to visit the north of Vietnam is from September to December when it isn’t so humid. The weather turns quite cold and wet in January and this continues until March. The humidity can prove oppressive from May to the start of September and there’s a danger of flooding. The South December to April is the best time to visit the south of Vietnam. There are short downpours during the wet season from May to November but they tend to only last a short time so you can still enjoy a visit during these months (just go for lunch when you see the black clouds developing). The Mekong Delta can experience severe flooding during this period making travel very difficult. The Center December to March is a good time to visit the Central Highlands when conditions are usually dry and cool. We visited the region in late November when the weather was beautiful with fine, warm days and pleasant evenings. We had a few light showers as we headed north towards Hoi An. Along the central coast there is a rainy season from December to February. June to October tends to be very dry and hot. Conclusion If you’re planning a trip to cover all of Vietnam the best time to visit is from September to December or from March to April.