December is a great time to visit Vietnam’s southern beach resorts including Mui Ne, Phu Quoc and Con Dao as this time of year normally sees long sunny, cloudless days with little rain.
Saigon and the Mekong Delta see similarly settled and ideal conditions.
Nha Trang further north has it's own micro-climate and December can see higher rainfall in Nha Trang.
Hoi An can be cooler at this time of year with temperatures in the low 20’s, sometimes not warm enough to lay by the pool. Some rainfall can be expected on most days, usually in the form of the occasional late afternoon downpour.
In Hanoi, temperatures can be an issue in December, when it can be quite chilly at night and in the early mornings. Jackets required!