Daga watan Mayu zuwa Oktoba, kudu maso yammacin monsoon yana kawo ruwan sama mai yawa fiye da millimeters 4,000 (160 a) zuwa kudancin kudancin kuma akwai lokacin bushewa a cikin hunturu. Ƙarin arewa, ruwan sama yana da ƙarancin, na 600 zuwa 700 millimeters (24 zuwa 28 in), wanda aka rubuta a lokacin Yuni-Agusta. An ce bambanci tsakanin matsakaicin da mafi ƙarancin kwararar kogin a cikin monsoon da watanni masu bushewa ya ninka sau 20. Kogin Manas, mafi girma a arewacin gefen kogin Brahmaputra, ya yi rikodin matsakaicin fitarwa na cubic mita 7,641 kuma yana ba da gudummawar kashi 5.48% na yawan kwararar Brahmaputra.
41,350 murabba'in kilomita (15,970 sq mi)