Mekong River Delta Vietnam was formed from silt and sediment accretion through the era of sea level change and through each period, leading to the formation of sand dunes along the coast. The mixture of rivers and sea has formed the fertile alluvial soil along river dikes, along some sand dunes, and coastal acid-sulphate soil on low-lying sediments such as in Dong Thap Muoi, Long Xuyen – Ha Tien, in the southwest of Hau River, and Ca Mau Peninsula. The topography of the area is relatively flat with the average height of 3 - 5m, even only 0.5 or 1-meter area above the sea level.
Weather in Mekong River Delta is characterized by humid tropical climate and sub-equatorial climate. The average temperature is 24°C – 27°C. The annual temperature range is about 2-30°C. The difference between day and night temperatures is low; there are few storms or weather disturbance. There are two distinct seasons in this region: rainy season lasting from May to November with the rainfall accounting for 99% of the total annual rainfall; while, the dry season running from December to April with less, even almost no rain. It is said that the climatic factors of the area are suitable for developing all type of agriculture. This weather is a prerequisite for intensification and cultivation.
Located in the tropical monsoon climate with high humidity, adjacent with Southeast Vietnam, so the characteristics of weather in Mekong Delta River are specific to the region. As mentioned above, the average monthly temperature of the region is about 27°C, thus weather in region is quite hot and humid. Often, April is the hottest month in a year with the average temperature of 28.9°C, while January is coolest month with the lowest average temperature of 25.2°C. Annual rainfall in Mekong Delta River fluctuates from 966 -1325 mm. The rainfall comprises 70-82% of the total annual rainfall. Rainfall is unevenly distributed, decreasing from adjacent areas of Ho Chi Minh City to areas in the west and southwest. Districts in the southeast near the sea have the least amount of rainfall. The high intensity of heavy rain causes erosion in high hills, at the same time, rain combined with tidal power causing flooding, which affects production and livelihood of the population. The humidity averages 80-82%. Lighting time per day ranges from 6.8 to 7.5 hours per day and 2500-2800 hours per year.
In dry season from December to April, climate in Mekong River Delta Vietnam is affected by the northeast monsoon with the frequency of 60-70%. Meanwhile, the rainy season from May to November, the region is influenced by the southwest monsoon with a frequency of 70%. Dry season seems to be the best time of the region. During this time, the region is describe by azure sky, lush vegetation and calm rivers. It will probably hot and humid during June to September, but, this condition of weather will provide a wide range of tropical fruits and flowers. Life in Mekong Delta is woven by water and season. It is most vibrant in late dry season with various types of flowers and fruits; therefore, that would be the best time to visit the region in particular and other places nearby such as Ho Chi Minh City and Vietnam in general.