The month of October was the coldest in 58 years in the national capital, the India Meteorological Department said on Saturday.
The mean minimum temperature last month was 17.2 degrees Celsius, the lowest since 1962, when it was 16.9 degrees Celsius, the IMD said. Normally, Delhi records a mean minimum temperature of 19.1 degrees Celsius in October.
On Thursday, mercury plunged to 12.5 degrees Celsius in Delhi – the lowest for the month in 26 years.
Kuldeep Srivastava, the head of the IMD's regional forecasting center, said the absence of cloud cover is a major reason for such low minimum temperatures this time. Clouds trap some of the outgoing infrared radiation and radiate it back downward, warming the ground. Another reason is calm winds, which allow formation of fog, he said.