Hotter days, warmer nights, heavier rain; Kolkata's climate set for sharp shift by 2040
Times of India | 19 June 2026
KOLKATA: Kolkata is likely to get hotter, more humid and wetter over the next two decades, with rising temperatures, warmer winter nights and more episodes of intense rainfall expected to make life increasingly difficult for residents, according to new climate projections.
The projections for 2021-2040, compared with the 1960s baseline period, suggest the city could see more heat-related health risks, particularly for people who spend long hours outdoors, while heavier bursts of rain may put additional pressure on Kolkata's ageing drainage network and increase the risk of flooding in low-lying neighbourhoods.
The annual mean temperature in the district is projected to reach 27.6°C (±1.67°C), while daily maximum temperatures are expected to average 32.45°C (±2.2°C). During summer, the mercury could touch 41°C (±2.3°C), while winter minimum temperatures are projected to remain around 11.4°C (±2.5°C).
The rise in humidity is expected to compound the impact of high temperatures. Annual relative humidity is projected to average 70.2%, rising to 85.6% during summer. The summer wet bulb temperature, an indicator of heat stress, is projected to reach 23.3°C.
The report also projects around 7.3 days every year when maximum temperatures could exceed 40°C, increasing the risk of heat-related illnesses among outdoor workers, street vendors and other vulnerable groups.
While summers are expected to become more oppressive, winters may gradually lose their characteristic chill. Warmer winter nights could affect farming communities that rely on seasonal temperature patterns for crop planning and cultivation, potentially disrupting traditional agricultural practices and food production.
Rainfall is also projected to become more intense. Annual rainfall is estimated at 1,631 mm, with nearly 1,263 mm expected during the southwest monsoon. The city could witness a maximum five-day rainfall of around 160 mm, while very heavy rainfall days exceeding 20 mm are projected to occur about 22 times during the southwest monsoon each year.
Such intense rainfall events are likely to overwhelm the city's drainage infrastructure, triggering waterlogging and increasing flood risks in densely populated and low-lying areas, the projections warn.
The findings are based on CMIP6 bias-corrected climate projections for Kolkata district under the SSP2-4.5 emissions scenario, covering the period from 2021 to 2040.