13 trains had to be cancelled due to poor visibility while 21 trains are running late. (Representational Image)

New Delhi: Dense fog enveloped the national capital on Wednesday morning, leading to cancellation of 13 north-bound trains.

The mercury also dropped to 5.6 degrees Celsius, two notches below the season's average although it was  recorded at 9.1 degrees Celsius.

According to the Northern Railways, 13 trains had to be cancelled due to poor visibility while 21 trains are running late.

The timing of four trains was rescheduled owing to bad weather.

At Safdarjung observatory, visibility was recorded at 200 meters at 8.30 am while the same recorded was 650 meters at Palam observatory.

According to MeT department, humidity level registered at 8.30 am was 100 per cent.

"The skies will remain clear throughout the day and the maximum temperature is expected to hover around 23 degree Celsius," an official of the department said.

On Tuesday, the maximum temperature was recorded at 25.5 degrees Celsius, six notches above the season's average.