The national capital recorded a minimum temperature of 11.4 degrees Celsius on Sunday morning, the lowest this season so far, according to the India Meteorological Department.
Normally, the Safdarjung Observatory, which provides representative data for the city, records a minimum of 15 to 16 degrees Celsius in the first week of November. The mercury dips to 11-12 degrees Celsius by the last week of November, it said.
Kuldeep Srivastava, the head of the regional forecasting centre of IMD, said the absence of cloud cover was the major reason for the low minimum temperature.
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 mist and fog, Mr Srivastava said.
There hasn’t been much snowfall in the hills, so cold winds from that region are yet to start affecting Delhi’s weather, he added.
The month of October was the coolest in 58 years in the national capital, according to IMD.
The mean minimum temperature in October this year was 17.2 degrees Celsius, the lowest since 1962, when it was 16.9 degrees Celsius, it said.
Normally, Delhi records a mean minimum temperature of 19.1 degrees Celsius in October. The city recorded a mean minimum temperature of 17.5 degrees Celsius in October 2007, according to IMD.
On Thursday, Delhi recorded a minimum temperature of 12.5 degrees Celsius — the lowest in October in 26 years.
The last time Delhi recorded such a low temperature in October was in 1994. The national capital had recorded a minimum of 12.3 degrees Celsius on October 31, 1994, according to IMD data.
The city recorded the all-time lowest temperature (9.4 degrees Celsius) on October 31, 1937, Mr Srivastava said.
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