Calcutta, Nov. 26: Winter is here, officially.

The chill in the air was perceptible today with the minimum temperature dipping to 16.8 degrees. It was 18.2 degrees Celsius yesterday.

The Met office said the dip in the minimum temperature to below 17 degrees heralds the arrival of winter in the city, provided an unhindered north wind and a clear sky accompany it.

“Unlike monsoon, which has a fixed probable date of arrival and departure, there is no such for the winter. Usually, it’s the 17-degree mark that we go by. As today’s minimum temperature is just below it, we can say that winter has arrived,” said A.K. Pal, a senior Met department official.

He added that in the next few days, with no possibility of formation of any low-pressure trough, the temperature is likely to drop further, though not too rapidly.

A week-and-a-half ago the temperature had fluctuated sharply over a couple of days, prompting many to believe that winter had arrived.

Experts in the Alipore Met office, however, said that the drop in temperature then was not accompanied by the north wind and was, therefore, a temporary phenomenon. Then, a low-pressure trough over the Bay of Bengal had stood in the way and, as a result, temperatures shot up again.

This time, though, that is unlikely, “The north wind is blowing lightly, at speeds between 1-2 knots a mile. And the sky is clear. Once the wind speed picks up and rises to between 3-4 knots a mile, the chill can be felt more,” Pal said.

The early-morning nip, which the city was getting accustomed to over the past few days, today remained till early afternoon, prompting many to pull out woollens.

On the outskirts, the pinch was even harder with the wind blowing faster and the temperature remaining low.

Met officials said the early morning haze over the city was largely a result of a mix of fog and dust particles. The first half of the day appeared cloudy because of this haze.

“It is natural at this time of the year. In the next few days, the temperature is likely to go down and stay within 16-15 degrees,” the official added.

The sky may be clear in the city, but the weathermen predicted rain in sub-Himalayan Bengal and Sikkim.