In northern Vietnam, March is a transition period from winter to spring. The weather in Halong Bay reflects this transition. In the beginning half of the month, cold winds may arise and there will be a chill to the air, leftover from the previous winter months of January and February.
As the month moves forward, the second half gradually becomes a bit warmer as spring approaches. The average temperature for the month of March is 19.5 degrees Celsius, while the maximum temperature increases to around 22 degrees Celsius during the latter half of the month. The minimum temperature drops to around 17 degrees Celsius during the night. Much like the rest of northern Vietnam, humidity levels increase during this time of the year and the number of wet days increase as well, signifying the land getting ready to flourish and grow. The number of wet days is around 13, with a total monthly rainfall of about 43mm. The length of daylight increases as well to around 12 hours per day, with the length of sunshine at around 3 hours per day.
In terms of planning a Halong Bay cruise in the month of March, it would be wise to check online for updates about the weather in Halong Bay, especially in terms of rainfall. Packing warm clothes is also important for the chilly nights, and wearing layers will help a lot with the fluctuation in temperature. With the average sea temperature slowly rising throughout the month to 22 degrees Celsius, water activities such as kayaking can still be fully enjoyed.
If you plan an active cruise that includes bike riding on Cat Ba Island or walking up and down steps of large caves, the Halong Bay weather in March can be perfect for these activities. It is not too cold to enjoy the outdoor weather and not too hot to cause over exhaustion. Feeling a cool breeze with increasing warmth in the air can be great for cruising.