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Climate overview |
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VietNam is rather larger than Britain and about half the size of the state of Texas.
Extending between 9° and 23° N, it lies entirely within the tropics. It has a long coastline on the Gulf of Tonkin and
the South China Sea. On the landward side it borders China in the north and Laos and Cambodia in the west. |
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Like other countries of the region, it has a tropical monsoon climate dominated by south to
southeasterly winds from May until September and northerly to northeasterly winds between October and April. There is a
twice-yearly period of variable winds at the time of transition from the north to south monsoon. |
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There are considerable areas of high land rising to over 2,450 metres/8,000 feet,
particularly in the northwest and in the central highlands facing the South China Sea. In the north around Ha Noi and
in the south around Ho Chi Minh City/Saigon there are extensive low-lying regions in the Red River delta and the Mekong
Delta respectively. These two lowlands contain a large proportion of the population and the productive rice-growing
areas. |
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The general features of the climate of VietNam also apply to the two adjoining countries,
Laos and Cambodia; all three countries are often grouped together under the name Indo-China. Over most of Indo-China
there is a single rainy season at the time of the south monsoon between May and September. |
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During the rest of the year rainfall is infrequent and light. Annual rainfall is almost
everywhere above 1,000 mm/40 in, and rises to between 2,000 mm/80 in and 2,500 mm/100 in on the hills, particularly
those facing the sea. |
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On the coast and in those parts of the Central Highlands that face northeast, the season of
maximum rainfall is between September and January. This area often receives heavy rain from typhoons, or severe
tropical storms, which develop in the western Pacific at this time of year. This is also a time of much cloud and
frequent drizzle (called locally the mua bui, sometimes crachin). |
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In the north of VietNam there are more cloudy days with occasional light rain during the
period of the northeast monsoon. The south of the country is more likely to be dry and sunny at this time. Compare the
tables for Ha Noi and Ho Chi Minh City. |
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In the southern and central parts of Indo-China, temperatures remain high around the year,
but in the north there is a definite cooler season as the north monsoon brings colder air from central China from time
to time. |
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Frost and occasional snow only occur on the highest mountains in the north for a few days a
year. In the south of VietNam, and in Cambodia and Laos, the lowlands are sheltered from any such outbreaks of colder
northerly air and the dry season is warm to hot with much sunshine. |
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The weather of VietNam, Laos, and Cambodia is rather sultry and oppressive during the rainy
season and the humidity is high at this time. On the coast and in the hills the frequent cloud and high humidity
combine with lack of sunshine to make this time of the year rather unpleasant in spite of the reduction of temperatures
with height. |
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Drought Disasters and Prevention |
Water is VietNams most important factor for domestic use, animal feeding, cultivating and
for industrial production.
Being a tropical, monsoon and redundant rainfall-country, Viet Nam has a blooming
agriculture, especially in water rice cultivation. |
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Recently, yielding the 'doi moi' policy, and modern technology, agricultural
extension and agriculture production achieve number of valuable results. |
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From a country which had to import food stocks in the past, VietNam is now becoming the
second country in the world for food stocks exporting. Agriculture extension and yield improvement for rice as well as
for other crops require water irrigation at right cropping time, with proper quantity and good quality due to crop
water requirement. |
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According to geographical and climatologic conditions, rainfall distribution in VietNam is
not equal both in space and time; the difference amount of rainfall between high-rain area and low-rain area is
tremendous; in high-rain area, annual amount of rainfall may reach to 5000 mm while 800 mm in low-rain area. This is
one of causes of drought. |
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Recently, climate changes and environment deterioration by human which cause protective
forest destruction, surface and ground water reduction and result in drought. |
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Thought must be given to the role of water in agriculture production, the State of VietNam
pays much attention to water resources construction to take part in agriculture development, to hold fast the food
security of country, to solve the problem of clean water for people and animals in mountainous area and in
frequent-drought area. |
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With the support of the UNDP Ha Noi - a United Nations Agency, and the former Ministry of
Water Resources (the Ministry of Agriculture and Rural Development instead), 'Strategy and Action Plan for water
disaster mitigation in VietNam' has been built and participated in water disaster mitigation in VietNam. |
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Storm and Weather Warnings |
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