Severe cold, fog set to welcome New Year: IMD

A potent combination of atmospheric forces—including the polar vortex, an Arctic blast and a western disturbance—has set the stage for severe cold conditions across northern India, with dense fog and cold day warnings issued through the New Year, the India Meteorological Department (IMD) said on Tuesday.

Dense to very dense fog is likely to persist during night and morning hours over Punjab, Haryana, Chandigarh and western Uttar Pradesh on December 31, with eastern Uttar Pradesh remaining affected until January 1. Cold day to severe cold day conditions are forecast over pockets of eastern Uttar Pradesh and Bihar until Wednesday.

Under the influence of the western disturbance, heavy rain and snowfall are expected over Jammu and Kashmir and Ladakh until January 1.

Multiple meteorological phenomena are currently driving the harsh conditions. A western disturbance — manifesting as a trough in middle tropospheric westerlies — is impacting the western Himalayan region, while a subtropical westerly jet stream with ferocious core winds of 259km/h at 12.6km above mean sea level continues to influence weather patterns over Delhi.

“We can see the influence of the polar vortex which affects the jet stream, which in turn influences the path of western disturbances. This leads to cold conditions over north India. There is some influence from the Arctic blast also,” said OP Sreejith, scientist and head of the climate monitoring and prediction group at IMD.

The convergence of these systems creates ideal conditions for both the persistent fog blanketing the plains and the extreme cold gripping the region. Additional weather systems—including a trough in easterlies over the southeast Bay of Bengal, and upper air cyclonic circulations over northern Kerala and northeast Assam—are adding to the complexity of the weather pattern.

Mahesh Palawat, vice-president of climate and meteorology at Skymet Weather, warned that minimum temperatures could drop further once the western disturbance passes. “It can become very cold over the plains as well,” he said.

There could be some rain and snow over these regions too. Isolated to widespread heavy rainfall and snowfall are very likely over Jammu and Kashmir, and Ladakh during December 30 to January period1. Isolated to scattered light or moderate rainfall and snowfall are expected over Himachal Pradesh and Uttarakhand until January 2.

Isolated light to moderate rainfall is likely over Punjab, Haryana and Chandigarh on Wednesday and Thursday, and over western Rajasthan on Wednesday.

Minimum temperatures dropped below 4°C at many places over Kashmir, Ladakh, and at a few places over Himachal Pradesh. Readings ranged between 4°C and 10°C at many places over Uttarakhand, Madhya Pradesh and northern Rajasthan, and at scattered locations across Odisha, Uttar Pradesh, Marathwada, Gangetic West Bengal and Chhattisgarh.

Temperature departures were appreciably below normal (minus 5°C to minus 3.1°C) at isolated places over central parts of eastern Madhya Pradesh, northern interior Odisha, Chhattisgarh, Gangetic West Bengal, Jharkhand and northern interior Karnataka. The lowest minimum temperature of 3°C anywhere in the country’s plains was recorded at Nowgong in eastern Madhya Pradesh on Tuesday.

Dense to very dense fog (visibility under 50 metres) blanketed parts of Odisha, Punjab, Haryana, Chandigarh, Uttar Pradesh and western Madhya Pradesh on Tuesday. Dense fog (visibility 50-199 metres) affected isolated pockets of Himachal Pradesh, Uttarakhand and eastern Madhya Pradesh.

The fog has led to widespread disruptions across air, rail and road networks, with commuters facing significant delays.

IMD warned of an increased likelihood of illnesses such as flu, runny or stuffy nose and nosebleeds, which typically develop or worsen due to prolonged cold exposure.

“Do not ignore shivering. It is the first sign that the body is losing heat,” the advisory stated. Frostbite can occur from prolonged exposure, causing skin to turn pale, hard and numb, with black blisters eventually appearing on exposed body parts such as fingers, toes, nose and earlobes. Severe cases require immediate medical attention.

Agriculture, livestock, water supply, transport and power sectors could also face disruptions in affected areas.

A cold day is declared when temperatures fall below 10°C and the maximum temperature remains 4.5°C to 6.4°C below normal. A severe cold day occurs when the departure exceeds 6.5°C.

Unlike typical cold waves that affect night-time temperatures, cold day conditions pose unique public health risks by limiting solar radiation during daytime hours when people are typically outside their homes.