The Celsius plunged to 12.1 degrees on Sunday, four notches below normal, riding strong north-westerly winds.

The recent cold spell was briefly broken on Saturday, when the minimum temperature was 15.3 degrees. But fresh cold winds from snow-laden Kashmir dragged the mercury down in the city on Sunday.

The next two days are tipped to see the Celsius sliding further, the Met office has said.

“The minimum temperature is expected to go down to the 11-degree range over the next two days,” said a Met official.

Sunday was the coldest January 31 since at least 2013, according to the Met office records. The minimum temperature on January 31 was 12.5 degrees in 2019 and 12.6 degrees in 2013.

The temperature has dropped below 10 degrees in several districts in the western part of the state. The Met office will declare a cold wave in places like West Burdwan, Birbhum, Bankura and West Midnapore if the chill persists, said the official.

The entire north India is under the grip of biting cold. The Celsius plunged to 3 degrees in Delhi and around 4 degrees in Patna. The winds from Kashmir reach Calcutta via both these places.

Last week was persistently cold in the city but moisture-laden winds from the Bay of Bengal led to cloud formation on Saturday and pushed the temperature up.

But the same clouds kept the maximum temperature under check and the day still felt cold despite a three-degree rise in the minimum temperature from Friday, when the mercury had plunged to 12.7 degrees.

The sky cleared by the night, accelerating the flow of north-westerlies. The early hours of Sunday were exceptionally windy and chilly. The day was mostly sunny and people flocked to the zoo, Science City and Eco Park in tens of thousands.

Even in the afternoon sun, pedestrians were wrapped in woollens.

“The cold weather is expected to persist till February 3, after which the temperature will start rising,” said G.K. Das, the director of Indian Meteorological Centre, Calcutta.