The climate in Vietnam differs greatly between north and south, though both regions experience monsoons. From November to April, the north is cool and dry, while May to October is hot and rainy. North of Nha Trang, the central coast has a similar climate with cool, wet weather between December and February in the winter monsoon season. The seasons tend to begin a bit later in the south, which is hot and humid all year round, particularly from February to May, while the rainy season lasts from May to November. The Central Highlands have a similar climate to the south, but is somewhat cooler and temperatures can reach freezing in winter. The temperature in Hanoi can range from 63°F (17°C) in January, to 84°F (20°C) in June.
++ Hanoi Capital Weather
Hanoi has a humid tropical climate, characterised by monsoons, like most of northern Vietnam. Summers, between May and September, are very hot with plenty of rain, while winters, from November to March, are cold and relatively dry. During the transition months of April and October anything is possible, and spring often brings light rain. The hottest month of the year is June. January is the coolest month, usually beset with a cold north-easterly wind.
++ Ho Chi Minh City Weather
Ho Chi Minh City is in the tropics, and very close to the sea, so its climate is steadily warm to hot all year round. Temperatures are slightly cooler between December and April, which is also the dry season. Rains begin in May and become heavy from June to August, but the showers are sudden and short, with the sun usually reappearing fairly quickly. There is a danger of typhoons from July to November.
Every year there are 100 rainy days , with an average rainfall of 1,500 to 2,000 mm. The humidity ranges from 80% to 99%. The average solar radiation is 100kcal/cm2 in a year.
Due to the monsoon influences, the average temperature in Vietnam is lower than that in other countries which are located on the same latitude in Asia. The annual average temperatures range from 22oC to 27oC. So one can expect colder winters and cooler summers in Vietnam.
Under influence of monsoon, and further because of the complicated topography, the climate in Vietnam always changes in one year, between the years, or between the areas (from North to South and from low to high). The climate in Vietnam is also under disadvantage of weather, such as typhoons (advantage there are 6-10 storms and tropical low atmosphere in year, floods and droughts are threaten the life and the agriculture of Vietnam).
Please re-check at the at the following link to update the Vietnam weather before you travel : http://www.vnbaolut.com/
Travel Guies in 67cities and Provinces of Vietnam: