Unlike other Asian destinations there is no best or worst time to visit Vietnam. The country stretches for almost 2000km north to south and seasons are different throughout all its regions. North Vietnam including Hanoi, Halong Bay & the Sapa Highlands can be rather cold and misty between November and March, at the same time however there will also be many clear and sunny days. Central regions including Hue, Da Nang & Hoi An receive most of their rain during September through to mid-January. This time of year the occasional typhoon may be formed on the southern China Sea and we would therefore advise you to avoid visiting this area from September to December.
South Vietnam, including Saigon and the Mekong Delta, are hot all year round with the traditional tropical downpour passing by. Overall probably the best time to visit Vietnam is between May and August. During this period, North and Central Vietnam are mainly dry with clear skies and the south – hot and humid with the occasional thunder storm.