
Below normal temperatures on most nights this month has pushed this November to be the coldest in at least a decade, data from the India Meteorological Department (IMD) shows.
The average minimum or night time temperature so far for the month until Sunday was 10.3 degrees Celsius — the lowest since at least 2011. This is also lower than the mean minimum temperature for the month, 12.9 degrees Celsius, which is based on data from 1981 to 2010, as per IMD.
Four cold wave days — when minimum temperature dips to 10 degrees Celsius or lower and the departure from normal temperature is 4.5 degrees or less — were recorded this November. Since 2011, Novembers in 2014 and 2013 have recorded only one cold wave each.
Minimum or night time temperature in the capital rapidly fell after November 16 — from 16 degrees Celsius to 6.3 degrees Celsius on November 23.
This was the lowest reading of minimum temperature for the current month since November 29, 2003, when mercury dipped to 6.1 degrees Celsius at night.
Minimum temperatures this month have also remained below normal on all days except on November 16 and 17, when rainfall and cloud cover over the city had helped increase the temperature.
IMD officials said a reason behind the dip in temperatures is the snowfall in high altitude areas north of Delhi in Himachal Pradesh, Jammu & Kashmir and Uttarakhand. Cold northwesterly winds blowing from these areas towards Delhi have been bringing down the temperature.
Additionally, clear skies over Delhi for most part of the month, which causes higher radiation at night, and the La Niña weather pattern may have helped bring down minimum temperatures.
Kuldeep Srivastava, head of IMD’s regional weather forecasting centre in Delhi, said the minimum temperature is expected to be below normal for the rest of winter in the capital.
On Sunday, the minimum temperature recorded at the IMD’s Safdarjung observatory, which is representative of Delhi, was 7 degrees Celsius, three degrees below normal. It is forecast to remain seven degrees on Monday as well.