Moderate to dense fog during the early morning hours disrupted rail services leading to cancellation of 40 trains and delayed 18 others.
However, flight operations remained normal.
Visibility fell from 1,000 metres at 5.30 AM to 700 metres at 8.30 AM while humidity was at 87 per cent.
Trains that are running behind schedule include Purushottam Express and Mahabodhi Express, a railways official said.
Following an overcast morning, the sun came out of the hiding around 10 AM. Weatherman said the day will witness mainly clear sky and a maximum temperature of around 17 degrees Celsius.