The India Meteorological Department on Monday said “cold wave conditions” were likely to develop in several parts of North India, including Haryana, Punjab, and Delhi from Wednesday because of clear skies and low wind speed.

“Cold day conditions likely to abate over northern plains of India from December 25 and cold wave conditions likely to develop over Punjab, Haryana, Chandigarh and Delhi and north Rajasthan from December 25,” said the weather department.

Weather conditions ranging from “cold to severe cold day” were expected at a few places in Punjab, Haryana, Chandigarh, and the national Capital till Wednesday, the bulletin added. According to the Met department, isolated areas in Uttar Pradesh may witness cold day conditions till Tuesday.

A “cold day” classification is used when the maximum temperature, or day temperature, dips below a specific mark. A cold wave is declared after the night temperature plunges. A severe cold day is recorded when the maximum temperature is at least 6.4 degrees Celsius below normal, and the lowest temperature goes below 10 degrees Celsius. A cold wave is recorded when minimum temperature is under 4.4 degrees Celsius below normal in at least two stations of a meteorological subdivision.

The weather department predicted that “dense to very dense fog” would be seen in the mornings in Punjab, Haryana, Chandigarh, Delhi and West Uttar Pradesh, and at isolated places over East Uttar Pradesh. Isolated places in North Rajasthan are also expected to be engulfed by dense fog in the morning in the “next four to five days”. A cyclonic circulation over Haryana and nearby areas, including Delhi and northwest Uttar Pradesh, was also prevalent.

Sunday was a severe cold day – the fifth one in a week – with a maximum temperature of 14.6 degrees Celsius, which is seven degrees below normal, Hindustan Times reported. A minimum temperature of 7.4 degrees Celsius was recorded.

“When a western disturbance moves away, there is cold air incursion from the higher reaches of Northwest India,” said K Sathi Devi, the head of National Weather Forecasting Centre. “There are usually clear skies and very cold nights, the combination of these conditions brings on a cold wave.” Devi added that the cold wave conditions may set in from Friday, but cold to severe cold days were likely to continue.