Season climatic type, at any place, associated with a particular time of the year. The change of season is mainly due to the change in attitude of the earth's axis in relation to the position of the sun at a particular place. In temperate latitudes four seasons are recognised: spring, summer, autumn (fall), and winter.

Summer (grisma)

Comprises Baishakh and Jyaistha (mid-April to mid-June), the two Bangla calendar months, when days are hot and dry. But the influence of summer is usually felt from mid-March. The heat of the sun dries up the waterbodies including the rivers, canals and the wetlands. The summer days are longer than the nights. The Bengali year begins with summer, with the Pahela Baishakh (first day of Baishakh) being the Bangla New Year.

The rainy season (barsa)

Traditionally spreads over Asadh and Shraban (mid-June to mid-August). However, the rainy season may start from the end of Baishakh and last up to the beginning of Kartik (mid-May to late-October). During the rainy season, the southwest monsoon winds bring plenty of rainfall (70 to 85 percent of the annual total) and occasionally lasting for days without end without any respite. Most of the floodplains of the country remain inundated during this period.

Autumn (sharat)

Lasts during Bhadra and Ashvin (mid-August to mid-October). This is traditionally the season when housewives put out clothes, musty and damp because of the rains, to air and dry in the hot sun of Bhadra. However, the bright day is often punctuated by sudden showers. The dark clouds in a grey sky, characteristic of the rainy season, are replaced by white clouds floating in a blue sky. Though at the beginning of this season, the days can be hot and sultry, towards the end of the season the nights and mornings become cool.

Late autumn (hemanta)

The fourth season, covers Kartik and Agrahayan (mid-October to mid-December). Actually it is a transitional phase between autumn and winter. By mid-November the evenings grow cool. The contrast between the daytime and nighttime temperatures results in heavy dew. This is also the time for colds, cough and fever. In this season farmers are very busy with harvesting paddy and celebrate navanna with the new rice crop.

Winter (shit)

The fifth season and the colder part of the year, in contrast to Summer, the hotter. According to the Bangla calendar it spreads over the months of Paus and Magh (mid-December to mid-February). But practically, November through February is the winter season in Bangladesh. Average temperatures in January vary from about 11'C in the northwestern and northeastern parts of the country to 20'C to 21'C in the coastal areas. Northern Bangladesh is cooler than southern Bangladesh.

The winter season is very dry, which accounts for less than 4 percent of the total annual rainfall. Average rainfall during the season varies from less than 2 cm in the west and south to slightly over 4 cm in the northeast.

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.

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.