Delhi's minimum temperature dipped to 7.8 degrees Celsius on Sunday, as cold winds from snow-clad Western Himalayas swept through the plains, the India Meteorological Department (IMD) said.
The mercury is likely to drop to five to six degrees Celsius by January 14, an IMD official said.
The Safdarjung Observatory, which provides representative data for the city, recorded a minimum temperature of 7.8 degrees Celsius, a notch above normal.
Delhi has registered above-normal minimum temperatures since January 3, as a cloud cover persisted over the city under the influence of successive Western Disturbances.
The city's minimum had settled at 10.8 degrees Celsius, four notches above normal, on Saturday, 9.6 degrees Celsius on Friday and 14.4 degrees Celsius on Thursday, the highest in January in four years, according to IMD.
The cloud cover over the national capital has prevented a steep decline in the minimum temperature so far, the IMD official said.
Clouds trap some of the outgoing infrared radiation and radiate it back downward, warming the ground.
However, the minimum temperature has started declining with the commencement of northwesterly winds from snow-capped mountains towards the plains starting Saturday, the official said.