The first hint of winter will be felt after sundown from the weekend, the Met office has said.
The minimum temperature rose on Friday because of increased moisture incursion between Thursday night and Friday morning. Dry northerly and northwesterly winds are expected to make significant inroads from Saturday, the minimum temperature is likely to slide below 20 degrees early next week, according to the forecast.
The minimum temperature was 24.8 degrees on Friday, up from 21.9 degrees the day before and almost four degrees warmer than usual.
"There were some easterly winds last night. The sky had turned partially cloudy. Any increase in the moisture level blocks the flow of cold and dry winds. But as Friday progressed, the moisture level dropped. Over the next few days, the cold and dry winds are set to dominate the atmosphere. The night temperature is likely to drop by three to four degrees by Tuesday," said H.R. Biswas, head of the weather section at the Regional Meteorological Centre in Alipore.
Real winter in Calcutta, with minimum temperatures of 15 degrees or lower, lasts barely a month from the middle of December to the middle of January.
But the proverbial nip in the air is something that the city yearns for well before the middle of December.
"Dry weather is most likely to prevail over all the districts," reads the official forecast for both south and north Bengal for the next seven days. There is no rain forecast.
Unlike the monsoon, there is no official announcement from the Met office on the onset of winter in Calcutta. However, three to four days without rain and a minimum temperature of less than 15 degrees usually mark the onset of winter.