Explained: As north India shivers, here are the factors that led to severe cold this winter

New Delhi, Dec 31: Winter tightened its icy grip across large parts of north India, particularly the national capital where the maximum temperature dipped to 3.7 degrees Celsius making Tuesday the city's coldest recorded December day since 1901.

With an early start to the cold conditions and a frequent drop in the temperatures, the people of Delhi have seen it all in the month of December itself. It should also be noted that December, usually, is not a peak winter month for Delhi.

So what are the factors?

Delhi has been experiencing a cold spell for 16 days now, which has been the highest since 1997. And it is very rare that the national capital sees temperature below 3 degrees during the month of December.

IMD officials have said that December 30 is that coldest recorded December day in Delhi since 1901.

Cold day and cold wave condition

This time, the residents of Delhi have been witnessing Cold day and cold wave conditions at the same time making both days and nights extremely cold. Usually, they rarely go hand in hand.

Western Disturbances

According to Kuldeep Srivastava, head of IMD's regional weather forecasting centre, Western disturbances in early and mid-December might be the reason that would have led to heavy snowfall in hilly areas and north of Delhi and also frigid winds have been blowing in from there.

Another western disturbance could have changed the wind direction away from Delhi, but an absence of such a weather system for 10-12 days aided the conditions for a harsh winter.

Mahesh Palawat of Skymet Weather, a private forecaster also said that this time the region has witnessed a long gap of 10-12 days between western disturbances. Usually, there's only a gap of 3-4 days in two WDs, and as a result, the wind direction keeps on changing. This time, the cold winds continued unabated from north-northwest for over 10 days in absence of a strong western disturbance.

Pollution

Meteorologists explain that pollution particles that serve as a surface for the condensation might be one of the reasons. The air quality index in Delhi was 421 in the severe category. Since air pollution accentuates fog which in turn plays a role in reducing day temperatures because fog blocks sunlight.

Climate Change

Extreme climates becoming more frequent might be another reason that has resulted in an unusual cold December this year.

The frequency and intensity of both heatwaves and cold waves have increased over the last several years, and are predicted to increase further.

Scientists say climate change is bringing in greater uncertainty in weather patterns, making them more difficult to predict.