The very shape and size of Vietnam, being long and thin and over 1,600 kms in length lends itself to each region having it’s own unique climate. Overall, temperatures are higher all year round for southern and central Vietnam. Northern Vietnam has a definite cooler season as the north monsoon occasionally brings in cold air in from China and the occasional typhoon between October and March.
Temperatures average between 12C & 25C. Frost and snow have been known in the higher mountainous regions of the north, only for a few days but transforming the landscape into a truly magical winter wonderland.
The south monsoon from May until September brings in very heavy tropical rainfall; however the climate remains a lot warmer than the north, with temperatures averaging between 24C & 32C. The central monsoon runs from September until January, and is typified by cooler days, clouds and frequent drizzle; however, typhoons can come in from the South China Sea bringing in torrential rain and high winds. Temperatures range from 19C to 24C during this time.
So, when would a good time be to visit Vietnam? Any time! Just avoid the above monsoon seasons and Vietnam has glorious weather. In general, the south will experience hotter weather and for longer sustained periods, however the central and northern areas of Vietnam are very welcoming weather nearly all year.