The minimum temperature in Kolkata went up to 16.8 degrees Celsius, two notches above normal, on Monday.
Only 48 hours ago, the city saw its coldest day of the season, with the mercury dipping to 13.2 degrees as cold northwesterly winds tightened their grip on the city.
After a very brief spell of chill, a warm phase is again in store for the city, said a Met official.
Christmas is also likely to be warm in Kolkata, the official said.
Friday and Saturday were probably the only days in December which felt like December.
“There is a cyclonic circulation over Bangladesh. As a result of the system, there is moisture incursion into Kolkata via the Bay of Bengal. The moisture has stalled the free flow of northwesterly winds from Kashmir and the mercury is on the rise,” said G.K. Das, director, India Meteorological Department, Kolkata.
“In Kolkata, the next few days are likely to see minimum temperatures between 16 and 17 degrees Celsius. The Celsius is unlikely to come down during Christmas,” he said.
The chill in winter is brought to Bengal by cold and dry northwesterly winds from Kashmir, which get intensified after a spell of snowfall.
The winds come via Punjab, Delhi, Uttar Pradesh, Bihar and Jharkhand.
The fluctuations in the temperature have left Kolkatans puzzled.
Woollens were in the cupboard for most of December. But on Friday and Saturday, they came out in most homes.
From Sunday, the mercury started going up again. And Monday was unusually warm.
“On Saturday, you needed a pullover even in the afternoon. But on Monday, keeping one on in the morning felt uncomfortable,” said Kajari Bhattacharya, a teacher at a south Kolkata school who has been busy with carnival preparations on the ground.
The city sky was gloomy for most of Monday.
“It was partly because of the moisture incursion and partly because of smog caused by air pollutants,” said a Met official.