November did not deliver the chill it had promised. December is here but woollens are still inside cupboards.

Since plunging to 15 degrees on November 23 and 24, the mercury has been on the rise, dashing the hopes of an early winter in Calcutta.

On Saturday, the maximum temperature in Calcutta touched almost 30 degrees. The Celsius has been dropping marginally in the night but the minimum temperatures have still remained a few notches above normal until Monday Tuesday.

The India Meteorological Department has forecast a harsher than usual winter for north and central India. Since cold and dry winds from the upper reaches of the country bring the chill to Calcutta, the forecast has raised fresh hopes of a longer and stronger tryst with the city’s favourite season.

The Met office in Alipore has cautioned against jumping into conclusions. “Severe cold in north India does not automatically translate to a lower than usual temperature in Calcutta. But the city can look forward to a decent winter this year,” said a Met official.

By “decent winter”, he meant “a few days of sub-12 degrees temperature” between December 15 and January 15.

In the “Seasonal Outlook for temperatures during December 2020 to February 2021”, the IMD said the north and northwestern parts of the country were set to experience a colder than usual winter this time.

Thanks to steady snowfall in the upper reaches of the country since November 15, winter has made an early entry in several northern states this year. The mercury has already plunged to six degrees in Delhi. But the biting cold in northern states has not brought a corresponding chill to Calcutta.

A series of weather systems over the Bay of Bengal — cyclone Nivar, that hit Tamil Nadu coast last week, being the latest of them — led to moisture incursion in Calcutta, stalling the free flow of northwesterly winds and triggering a rise in temperature.

Another well-marked low-pressure area was brewing over southeast Bay of Bengal on Monday.

“Not every system leads to rain in Calcutta. But it injects moisture into the atmosphere, triggering a rise in temperature,” said the Met official.

The minimum temperature dipped to 15.7 degrees on Monday. But the day was warm and sunny, with the Celsius climbing to 29.1 degrees.

“The minimum temperature is expected to remain in the 15-16 degrees range over the next few days. The maximum temperature will be in the range of 28-29 degrees,” said a Met official.

The Met office in Alipore does not formally announce the onset of winter. But December 15 is the usual time for winter to set foot in Calcutta, according to Met officials.

The key parameter is that the minimum temperature has to be 15 degrees or less for at least four days at a stretch.

The day temperature in the coming days will be an indicator of the chill, said G.K. Das, director, IMD Calcutta.

“If the day temperature is around 27-28 degrees, the mercury will go down to around 15 degrees. But if the day temperature is around 24-25 degrees, the minimum temperature is likely to dip to 12 degrees or lower,” he said.