Vietnam weather is known for its diverse climate. Below is a note from Gonexp.com of Vietnam weather so you know what to expect during your trip.
Vietnam weather has a tropical monsoon climate. Therefore, there are two main seasons, the southwest monsoon from April to September and the northeast monsoon from October to late March or early April. With the top North region on temperature zone. Provide that, its climate is not consistent throughout the country with the Southern being hot and wet while the Northern is rather cooler and wet
In fact, there’s a significantly variety of climate changes by latitude and longitude. So to make it easier, we will break it down to 4 areas: Mountainous Northeset Vietnam, Northern Vietnam, Centre Vietnam and Southern Vietnam.
There is a little different here in the two seasons with the dry season from October to late March with the wet season lasting from April to September. Particularly, there is a significant decrease in temperature that could result in frosty in December and January, especially at night.
The best time to visit Sapa is the dry season especially between September & November, as the flowers bloom, and from March to May, when the rice paddle turn golden before harvest. Besides, with the skies are clear this time of the year, you can also enjoy some trekking and adventure experience.
Dictated by the temperature zone, Northern Vietnam experience a cool to cold season (from November to March) and a warm to hot, wet season (from April to October). Particularly, during December and January, it can sometimes get quite frosty due to the heavy mist run for days.
If you are travelling to one of the most tourist attractions in Vietnam, try to visit from April to June or September to November. With the clear and sunny skies, enjoyable temperature, you can enjoy any outdoor activities without any hesitation. Also, if you want to experience the mystery side of Halong Bay, with its famous karsts surrounded in mist, January is not a poor choice. It might get humid but there’s still some warm feeling though.
Central Vietnam is the in-between area climate-wise from the north to the south. Truongson mountain range is like a wall blocking all the rain come with the southwest monsoon from other the coast.
Though, between September and December, the northern section of Central Vietnam (Hoi An and Da Nang through to Hue and Dong Ha) receive a considerable rainfall. So the best time to visit those places, is somewhat between March and April, with the fields, gardens and street covered in blossoms and scenery green.
Dalat, located in the centre highlands, is known for its refreshing and breezy. Specifically speaking, from November to May it stay dried, though sometimes cold in December and January. The mountainous geography constantly provides cool breeze and nice temperature. It’s an ideal time to visit this place in these times of the year, escape all the heat from the city. But, from June to October, Dalat is rather wet and rainy, so it may be troublesome to pursuit some outdoor activities.
Southern Vietnam and Ho Chi Minh city rather have a consistent weather year-round, it's either hot and dry or hot and rainy. The average temperature is around 30 degrees, though, there are some pleasant days and some scorching days mid-year. Without the protection of Truongson mountain range, it's raining season from June, July until November.
Further south though, the southern coastal strip from around Nha Trang to Mui Ne, Phu Quoc is less affected by the rain and sees a longer dry and sunny season. These places enjoy some of Vietnam's best beaches along the coastal. However, if not travelling on dry season, afternoon downpours should be expected.
As there are so many destinations in its best time around the year, it’s really undecided whether it is the ideal time to visit Vietnam. If you want to experience a nice, cool and dry weather of the Northern Vietnam; October, November and December is the perfect choice.
Otherwise, the coastal stretch from Hue to Nha Trang in the first half of the year is the place to be. And from November through February, you can consider the consistent temperature of Saigon and the Mekong Delta.