The minimum temperature dropped by as many as five degrees over 24 hours, from Tuesday's 21.5 degrees Celsius to 16.6 on Wednesday. November's long-term mean minimum temperature in Calcutta is 19.7. "The big fall in temperature that we were expecting has happened. If there is further fall in the minimum temperature over the next few days, it will be by one or two degrees. According to the IMD Calcutta website, the minimum temperature is about to fall to 15 degrees Celsius on Friday and then rise marginally to around 16.

Source: The Telegraph November 23, 2017 20:26 UTC