New Delhi, Jan 6 (IANS): It was a cold and foggy Saturday morning in the national capital with the minimum temperature recorded at 4.2 degree Celsius, three notches below the season's averag.

Visibility at 8.30 a.m. was 400 metres.

The Railways had to cancel 18 trains while 49 were delayed and 13 rescheduled due to fog in several parts of northern India.

Operations at the Indira Gandhi International (IGI) Airport here were affected due to the low visibility.

"Due to poor visibility in #fog at Delhi, Patna, Varanasi, Chandigarh and Lucknow some of our flights are affected," Jet Airways tweeted.

While early in the morning, SpiceJet, in a tweet, said: "Due to bad weather at Delhi, all departures/arrivals and their consequential flights may get affected. All passengers are requested to cross-check their flight status before leaving for the airport."

The sky will remain clear during the day, an India Meteorological Department official said.

The maximum temperature is likely to hover around 18 degrees Celsius.

Friday's maximum temperature settled at 18.1 degrees Celsius, one notch above the season's average while the minimum was recorded at recorded at 7.2 degrees Celsius, the season's average.