Bangladesh is called the land of six seasons (Sadartu). It has a temperate climate because of its physical location. Though the climate of Bangladesh is mainly sub-tropical monsoon, ie warm and humid; Bangla calendar year is traditionally divided into six seasons: Grisma (summer), Barsa (rainy), Sarat (autumn), Hemanta (late autumn), Shhit (winter) and Basanta (spring). Each season comprises two months, but some seasons flow into other seasons, while others are short. Actually, Bangladesh has three distinct seasons: the pre-monsoon hot season from March through May, rainy monsoon season, which lasts from June through October, and a cool dry winter season from November through February. However, March may also be considered as the spring season, and the period from mid-October through mid-November may be called the autumn.
The spring (basanta) The last of the seasons occurs between winter and summer, spreads over the Bangla months Phalgun and Chaitra (mid-February to mid-April). The spring season is very brief in Bangladesh and practically prevails during March only. During this season, winds are variable in direction because this is the time of transition between the northerly or northwesterly winds of winter and the southerly or southwesterly winds of summer. Weather is normally pleasant, with 20 to 25 percent cloud-cover, comfortable temperature and moderate relative humidity. Average temperature in March varies from 22’C to 25’C all over the country, with relative humidity ranging from 50 to 70 percent. However, temperature, cloud-cover and relative humidity during the early part of the season are lower than their respective average values. Occasionally, isolated thunderstorms may occur in the afternoon, especially during the second half of March.
Spring is called the king of seasons. The climate at this time is very pleasant and inspires people to take morning and evening walks. At this time the sky is clear and plants sprout new leaves. There are balmy breezes from the south, very welcome after the cold winter. Flame-coloured shimul, palash and krisnachuda blossom, as does the golden radhachuda and the mauve jarul. Fruit trees such as mango and jackfruit also flower at this time. Spring sees the advent of the cuckoo, which sings hidden in the foliage. This is also the season for bees to become active gathering nectar. Wheat, oat and mustard dominate the fields. Hindus celebrate pujas like Basanti and doljatra. In the past this season’ was marked by epidemics like cholera and smallpox (which was called basanta). Smallpox has since been completely eradicated and cholera largely controlled.
The seasons of Bangladesh regulate its economy, communication, trade and commerce, art and culture, and, in fact, the entire lifestyle of the people.