The IMD has four colour-coded warnings as per the intensity of any weather system -- green, yellow, orange and red. Orange alert is given to authorities to be prepared.

 

The Safdarjung Observatory, which provides representative data, recorded a minimum temperature of 4.4 degrees Celsius, while Ayanagar and Lodhi Road weather stations registered 3.5 and 3.8 degrees Celsius. The city is likely to record another "severe" cold day on Friday.

 

"Cold day to severe cold day at a few places and cold wave to severe cold wave conditions at many places. Ground frost at isolated places," stated IMD in its bulletin. The city will witness partly cloudy sky on Saturday and shallow fog for the three subsequent days.

 

According to the head of the India Meteorological Department's regional forecasting centre, Kuldeep Srivastava, the icy winds are blowing towards the national capital region from Jammu and Kashmir and Himachal, which had witnessed heavy snowfall on December 12.

 

Besides this, the whole northern plains is in the grip of a severe cold wave. Navdeep Dahiya, founder of Live Weather of India stated that Halwara in Punjab recorded the lowest temperature at minus 0.6 degree Celsius, followed by Churu in Rajasthan recoding minus 0.3 degree Celsius and Amritsar at 0.4 degree Celsius.

 

According to the weather department, there will be no significant change in minimum and maximum temperatures over parts of northwest India for the next two to three days till Monday and rise by 2-3 degree Celsius in minimum temperatures and 4-5 degree Celsius in maximum temperatures during subsequent three days till December 24.

 

"Cold day to severe dold day conditions very likely in some pockets over Punjab, Haryana, Chandigarh, Delhi and West Uttar Pradesh.

 

"Cold day conditions in isolated pockets over Jammu division, Himachal Pradesh, Uttarakhand, east Uttar Pradesh, Rajasthan and west Madhya Pradesh during next 24 hours (till Saturday) and decrease thereafter," IMD stated.

 

The IMD also issued alert for the ground frost over Delhi, Jammu and Kashmir, Ladakh, Gilgit-Baltistan, Muzaffarabad, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Chandigarh, west Uttar Pradesh and Rajasthan during the next two days till Sunday.

 

Ground frost refers to the various coverings of ice produced by the direct deposition of water vapour on objects and trees, whose surfaces have a temperature below the freezing point of water.