The geographical latitude of An Giang is approximately 10 – 11o northern latitude that is lying near to the equator, so the happening processes of the temperature as well as the rainfall are alike in the climate of the equator.
The condition of the circulation of atmosphere:
An Giang is effected by two seasons of wind: The Southwest monsoon and the Northeast monsoon. The Southwest monsoon is cool and wet therefore it causing the rains. The Northeast monsoon blowing into An Giang starts from the tropical sea in the side of China so the temperature being higher than the ice and snow area of Siberia and the humidity being larger, without creating feature but only hot and dry, having its share of hot and dry sunlight.
The meteorological elements:
a. The clouds:
The quantity of clouds in An Giang is relatively little. In the dry season, the sky is sometimes cloudy but is still sunny. In the rain season, the quantity of clouds usually has much more. The medium-month clouds amount of the dry months being 3.1/10 and of the rainy months being 6.9/10.N.
b. The sunlight:
An Giang having the intense dry season, becoming the province having numbers of sun hours in the year being very much large gaining the record of the whole country. On an average, the dry season coming up 10 hours of sunlight/a day; though the rain season has fewer but it still coming up nearly 7 hours of sunlight/a day. The total accumulation temperature of the year comes over 2,400 hours.
c. The temperature:
The average temperature in An Giang is not only high but also very stable. The differential temperature between months in the dry season is just larger or less than about 1,5o till 3o; and in months of the rain season is just about superiors and inferiors 1o. The highest temperature of a year always occurs in April, swinging in about 36o – 38o; the lowest temperature of a year always appears in December, under 18o (the years 1976 and 1998).
d. The winds:
In An Giang, in the dry season, the popular wind is the Northeastern wind, and in the rain season is the Southwest wind – the Southwest wind is the wind having the frequency appearing mostly. Speed of the wind in here being relatively strong, on the average achieving over 3m/a second. In a year, the speed of the summer wind is bigger than the winter wind. An Giang is the province lying deeply in the Nam Bo mainland so is rarely influenced by windstorms.
e. The rain season:
In An Giang, the rain season usually begins in May and ends in November. The total amount of rain of the rain season achieves 90% the total amount of a year. The rain-amount of the heavy rain season still coincides with flood waters season of the Mekong River concentrating on the lower section so brought up waterlogged situation combined with flood affecting to a great number of production activities and lives.
f. The vaporization:
In the dry season, because of a great number of sunlight, the humidity of the air being low so the amount of vaporizing being large, the average is 110mm/a month (coming up 160mmm in March), in the rain season, the amount of vaporizing is lower than, the average is 85mm/a month. The smallest amount is about 52mm/ a month occurring in September or December, being a period having the large number of rains, high humidity.
g. The humidity:
In An Giang, the season with the low humidity (smaller 80%) usually starts from December and extends till April next year. It means that, the season with the low humidity coincides with the dry season. In the dry season the humidity at the beginning time being 82%, at the mid time being 78%, at the end of time being 72% only. The rain season in here is actually the wet season. The average humidity in months of the rains is 84%, particularly there is a month achieving approximately 90%.
Apart from above meteorological elements, An Giang still has weather phenomenon needed to pay attention to such as: whirlwind–waterspout –hail –Ba Chan drought affected by El Nino and La Nina.