The climate of Mekong Delta is influenced by the Southwest Monsoon.
The monsoon season usually lasts from May to late September/early October.
Usually heavy rainfall in most regions
August, September, and October are the wettest month in most areas (tropical cyclones)
In late October to December, the temperatures are cooler due to the Northeast monsoon.
During this monsoon, Vietnam still receives rainfall
July, August, and September = generally months of highest rainfall in most regions
December, January, and February = months of lowest rainfall
Average annual rainfall is 1700mm during drought years, the annual rainfall in some regions can be as low as 650mm
Years of above average cyclones = wider impacts on the rainfall climate
Cyclone years become wetter than normal years
Over most of Lower Delta, during the tropical cyclone years, the chance that any given day will be wet is very high.
Southwest Monsoons combined with severe tropical cyclones can cause flood disasters in the Lower Mekong.
Climate Change Effects
Lower mean annual flows and floods
Seasonal distribution of water stays the same
Flood season volumes decrease by 15 percent