Kolkata sits on the Hooghly River near the Bay of Bengal and receives about 1,600 mm (roughly 63 inches) of rain a year, most of it during the summer monsoon from June through September, supplemented by occasional pre-monsoon thunderstorms known locally as “Nor’westers” that can bring sudden, intense downpours and squally winds. The city’s flat, low-lying delta terrain and aging drainage network mean that heavy monsoon rain, especially when it coincides with high tide on the Hooghly, can leave streets waterlogged for hours or days at a time. Bay of Bengal cyclones occasionally track close enough to the region to add extreme rainfall on top of an already active monsoon. Because flooding risk here tracks closely with short-term rainfall intensity and tidal timing rather than the season’s total alone, radar imagery is a genuinely practical tool for residents judging whether to delay travel during an active monsoon spell. The India Meteorological Department operates radar coverage for the Kolkata region.
Learn more: Flash Flood Warning Signs on Radar · Open the full Rain Map