Chilling climax to 2025: Delhi sees coldest December day in 6 years

The last time Delhi had a lower maximum in this month was in 2019 when it was 13.3°C on December 29.

The Capital recorded its coldest December day in six years on Wednesday, ending the year under a heavy winter pall marked by biting cold, dense fog, and a haze of pollution —its seasonal companions.

According to meteorological experts, the low maximum was a result of a prevailing active western disturbance kept humidity high, with easterly winds feeding moisture and facilitating fog formation. (Hindustan Times)

According to the India Meteorological Department (IMD), Delhi experienced “cold day” to “severe cold day” conditions as maximum temperature dropped dramatically on Wednesday, registering at 14.2°C, more than 6°C below normal and over 7°C from the 21.5°C a day earlier. The last time Delhi had a lower maximum in this month was 2019 when it was 13.3°C on December 29.

Under IMD’s classification, a “cold day” is when the minimum temperature drops below 10°C and the maximum temperature is 4.5°C or lower than normal.

While Delhi’s maximum and minimum are recorded at Safdarjung, other locations were even colder. “Severe cold day” conditions were logged at Palam (13.6°C) and Lodhi Road (13.4°C), temperatures were 6.8°C and 7.6°C below normal, respectively. It is classified a “severe cold day” when the maximum is 6.5°C or lower than normal.

The lowest maximum in the city was 13.1°C recorded at the Ridge station, but since it was 6.2°C below normal, it was a “cold day” as well. The minimum remained 6.4°C, which is largely normal for this time of the year.

According to meteorological experts, the low maximum was a result of a prevailing active western disturbance kept humidity high, with easterly winds feeding moisture and facilitating fog formation.

This also meant that despite winds picking up during the day, a thick layer of fog continued to push downwards from Punjab, shrouding large parts of the Indo-Gangetic Plain (IGP) region.

Upper-level clouds also made it difficult for sunshine to reach the surface, keeping the Capital locked in a haze of fog and pollutants and frigid temperature and disrupting travel plans as flight, rail and road travel were severely impacted. Delhi was swathed in grey as dense fog persisted for over fourhours and visibility fell to as low as 50 metres.

According to flight tracking website FlightRadar24, 150 flights were cancelled, over 500 delayed, and two diverted at Delhi’s Indira Gandhi International (IGI) airport. To be sure, a number of the cancellations had been made in advance. Over 100 trains were also delayed under the Delhi division of Northern Railways.

The air quality remained at the higher end of “very poor” for another day, with the 24-hour average air quality index (AQI) registering at 373 (very poor) at 4 pm. This marks the sixth straight day of ‘very poor’ to ‘severe’ air, including Tuesday’s reading of 388. Overall, Delhi recorded 27 such days this month.

What the forecast says

Explaining weather conditions in Delhi on Wednesday, Mahesh Palawat, vice president at Skymet, “Typically fog lifts up during the day, but we had ample moisture — over 80% during the day on Wednesday and despite winds, could not dissipate much — moving south and south west of Punjab. It stretched across the Indo-Gangetic Plains. We also had partial cloudiness in the upper-levels.”

Overall, this was the second “cold day” of the season. The first cold day of the season was recorded on December 20 (16.9°C).

To be sure, the IMD had forecast the possibility of dense fog in Delhi on Wednesday, but not “cold day” conditions. It had said the maximum is likely to be between 21-23°C on the last day of the year.

IMD has forecast a chilly start to the new year in the Capital with “cold day” conditions and very light to light rain likely on Thursday. Further, dense to very dense fog is “very likely” to persist till January 5, it said.

“Dense to very dense fog conditions are very likely to continue during night and morning hours over Odisha, Punjab, Haryana, Chandigarh and Delhi till January 5, while it is likely in east UP till January 2 and in west Rajasthan till January 3, 2026,” said the IMD in its national weather bulletin on Wednesday.

The Air Quality Early Warning System for Delhi (EWS) has forecast that the AQI will stay “very poor” in the coming days. “Delhi’s air quality is likely to be in the ‘very poor’ category from January 1 till January 3, 2026. The outlook for subsequent six days – from January 4 onwards shows the air quality is likely to be in the ‘very poor’ category,” said the EWS in its daily bulletin.