Southern Vietnam

There are 2 main seasons: dry and wet. The dry season in the south of Vietnam is from November to late April or May. The wet season is from May through October. 

Central Seaside Provinces of Vietnam 

There are two subregions: coastal lowlands and central highlands, which are east coastal provinces and west central highlands. The coastal area is usually dry and hotter than the rest in the summer, from April to October.

Central Highland in Vietnam

The Central Highlands, in particular, enjoy nearly double the country's average rainfall. The two biggest towns in this plateau, Dalat and Pleiku, are ideally cool throughout the year. 

Mekong Delta's Vietnam and Cambodia

The weather in the Mekong Delta has two distinct seasons. The rainy season, which lasts from May to last November, and the dry season, from May to last April. The weather is more relaxed from November to February. In general, the preferred travel time is from August to April in both the dry and wet seasons. It may be more humid and a little bit hot from May to July, when farmers start to make rice crops. However, this is also when travellers can embark on unique bicycle tours. Despite being the wettest months, from the last of May to August, the rains usually come in short, heavy showers, mainly in the afternoon, and only last for an hour. This creates a thrilling cycling experience, with the sunshine quickly returning to normal.

In the central provinces

The rainy season in Central Vietnam is usually around September until early January, which coincides with the best humidity and temperature of the year, with high levels of rainfall from September to November. Sometimes, typhoons from the sea affect Hoi An, and flooding might occur in Hoi An's old town from October to December. October until February is the peak season for tourism in the country. The dry season is between January & August, with temperatures ranging in the mid 30°C and humidity. In general, the weather in Central is divided into two seasons, and the rainy and dry seasons do not coincide with the two climatic regions of North and South. It's hot and humid from May to August, so it's the best time to do bicycle tours from September to April.

In the north of Vietnam

Hanoi and North Vietnam have two distinct winter and summer seasons. The relaxed but primarily dry winter lasts from November to April when temperatures average 17-22°C, the coldest months being December to February. It is hot and humid; summer lasts from May to October, with the highest rainfall from May to August.

In the Northeast, the rainy season usually occurs in May and ends in August with heat and low humidity, while the Far North's rainy season begins in June and lasts until August. In the Far North, the cold winter lasts from December to February.

North West and Far North Vietnam's agriculture depends on the wet season, particularly rice crops on terraces. Rice plants need plenty of water to grow and develop themselves. The yearly rice crop in the North West and the Far North is only one crop and will begin after the first rainy month to make the soil more workable before seeding starts. The times to seed the rice plants are from 2 weeks, depending on locations, high or low terraces, and how much water is from raining or getting from streams and rivers.

The best time to explore North West & Far North Vietnam is the farming season, not at the beginning, with too much rain and young seeling rice plants only. The harvest season is from early September to last October. Here are the opportunities for travelers to admire stunning, colorful rice-terraced fields, lush country farms, green rainforests, waterfalls, and vast vegetation. Travellers also meet hill tribes on farms and in their homes.

Cambodia

Laos

Thailand