Alipore: The winds of change are blowing. What gave the city a long cold spell in January is now pushing the mercury up in February, weather scientists said.

The poor frequency of Western Disturbances in Kashmir - a trend this season - is to blame for both weather conditions.

The minimum temperature in the city has been nudging 20 degrees Celsius, three degrees above normal for this time of the year, for the past three days.

In other years, the minimum temperature has dipped as low as 11 to 12 degrees Celsius in the first week of February (in 2012) or hovered between 12 and 13 (2014 and 2015). But this year the mercury climbed past 19 degrees just four days into February.

The days have been hot as well with the maximum temperature tipping touching 30 degrees Celsius.

Tuesday was, however, less uncomfortable than Monday because of a dip in the daytime humidity.

The weather is unlikely to change for now with little chance of the cool making a comeback, Met officials said.

Western Disturbances or storms from the Mediterranean hit Kashmir from time to time, moving from west to east. While it stays on the Indian landmass - often in the form of low pressure - it holds up the north-westerly wind blowing into Calcutta. The chill is felt once it passes because this releases the winds once more.

"In January, even if there is no strong Western Disturbance hitting Kashmir, the weather stays cold because the general direction of the wind remains north-westerly," said Sanjib Bandyopadhyay, deputy director general, India Meteorological Department. "But in February, no Western Disturbance hitting the valley means quite the opposite. It makes the weather in Calcutta and surroundings warm as other factors such as the changing angle of the sun and low pressure on the Bay of Bengal kick in."

With the sun travelling from the southern hemisphere to the north, the sun's rays are falling on the surface of the earth in a straighter line and pushing temperatures up. A cool north-westerly wind would have reduced both the minimum and maximum temperatures.

Two weather systems - a cyclonic circulation over north Bangladesh and a high pressure belt on the Bay of Bengal - have added to the summer-like feeling.