Bangladesh has a tropical monsoon-type climate, with a hot and rainy summer and a pronounced dry season in the cooler months. January is the coolest month of the year, with temperatures averaging near 26 deg C (78 d F), and April the warmest month, with temperatures ranging between 33 deg and 36 deg C (91 deg F and 96 deg F). The climate is one of the wettest in the world; most places receive more than 1,525 mm (60 in) of rain a year, and areas near the hills receive 5,080 mm (200 in). Most rain falls during the monsoon (June-September) and little during the dry season (November-February).
The coastal districts of Bangladesh , particularly those flanking the Meghna estuary, are susceptible to serious damage from cyclones, which cause major losses of life and property. In the early summer (April and May) and late in the monsoon season (September to November) storms of very high intensity often occure. They may create winds with speed of 100-150 miles per hour piling up the waters of Bay of Bengal to crests as high as 20 feet that crash with tremendous force onto the coastal areas and offshore islands. Since the early 18th century, when records were first kept, more than one million people have been killed in such storms --815,000 of them in three storm occuring in 1737, 1876 and 1970. Severe storms also occured in May 1985 and April 1991. Lesser hazards in the region are hailstorms, particularly in March and April, and tornadoes.
Bangladesh is one of the most flood-prone countries in the world. Essentially, it's the flood plain where two huge rivers--the Ganges and the Brahmaputra --carry spring snowmelt from the towering Himalayan Mountains to the sea. When the rivers flood, so does Bangladesh