Vietnam is more than 2,000 km long. Thus the climate varies greatly between the North, Central and South Vietnam. The best time to visit varies by region. Certain times of the year you may want to consider combining Vietnam with another neighboring country.
Best time to go by region
There are 4 seasons
best time for traveling: April - June & September - November
July - August: hot and humid (38°C)
August - September: risk of typhoons on the coast
December - January: cold and mostly dry (in mountains to freezing - no heating)
February - March: drizzling rains
November - March: risk of rain
A mountain chain between Hue and Hoi An causes a separation of climate, resulting in Hoi An and further south often being more pleasant and drier than Hue and further north.