The mercury dropped to 20.6 degrees in Kolkata on Monday, two notches below normal.
Since October 28, when the minimum temperature was 25.4 degrees, the Celsius has been on an uninterrupted slide.
The Met office has, however, ruled out the possibility of the minimum temperature plunging below 20 degrees for the next 48 hours. If anything, the slide will be arrested because of a weather system in Bangladesh, said a Met official.
“On Tuesday, a cyclonic circulation is likely to form over central Bangladesh. Under its impact, Kolkata and North and South 24-Parganas are likely to see moisture incursion and a cloudy sky on Tuesday and Wednesday,” said G.K. Das, director of India Meteorological Department, Kolkata.
According to the forecast, the sky will start clearing again from Thursday, when the city celebrates Diwali.
The Met office said the impact of the circulation was likely to be limited to cloud formation, almost ruling out the possibility of rain in Kolkata.
For the past few days, Kolkatans have been experiencing a nip in the air in the night and early morning.
“Cold and dry north-westerly winds from the upper reaches of the country are entering Bengal. South Bengal is feeling the effect of the winds,” said a Met official.
The weather in Kolkata has been dry for the past few days. The minimum relative humidity, which has been on the lower side, is tipped to climb up for the next couple of days.
Any increase in moisture levels in the atmosphere is a deterrent to the free flow of north-westerly winds.
“Most other districts of south Bengal will feel the effect of the north-westerly winds but Kolkata and North and South 24-Parganas are likely to see marginally warmer weather,” said the Met official.
“From Thursday, the sky is likely to be clear. By November 5-6, the mercury may drop below 20 degrees,” the Met official said.