Delhi's minimum temperature dropped to 9.6 degrees Celsius on Friday, a day after it rose to 14.4 degrees Celsius, the highest in January in four years, according to the India Meteorological Department (IMD).

A cloud cover persisted over the national capital, preventing a steep decline in the minimum temperature, an IMD official said.

Clouds trap some of the outgoing infrared radiation and radiate it back downward, warming the ground.

The Safdarjung Observatory, which provides representative data for the city, recorded a minimum temperature of 9.6 degrees Celsius as against 14.4 degrees Celsius on Thursday.

Delhi witnessed rainfall for four consecutive days till Wednesday under the influence of a strong western disturbance affecting northwest India.

A fresh western disturbance may lead to "very light" rain in the city on Friday. The weather will remain cloudy, officials said.

Thereafter, Delhi's minimum temperature is likely to dip by four to five notches with the commencement of northwesterly winds from snow-capped mountains towards the plains.

The IMD said Delhi has already recorded 56.6 mm rainfall in January, the maximum for the month in 21 years.

On average, Delhi records 21.7 mm rain in January every year. It had gauged 48.1 mm rainfall in January last year, 54.1 mm rainfall in January 2019 and 59.7 mm rain in January 1999.

The city had registered 69.8 mm rainfall in January 1995, according to IMD data.