hi there,
Vietnam’s weather is known for its monsoons. The winter monsoon comes from the northeast between October and March, bringing damp and chilly winters to all areas north of Nha Trang, and dry and warm
temperatures to the south. From April or May to October, the summer monsoon brings hot, humid weather.
Vietnam gets pretty crowded from November to March and in July and August. Prices tend to peak over the Christmas and New Year period.
Hope this helps
Vacationbuddy