"However, it will get colder towards the evening," an India Meteorological Department (IMD) official said.
The day temperature is likely to be around 17 degrees Celsius, the officials added. Humidity at 8.30 a.m was 89 percent.
According to a railway official, 10 trains were cancelled and 20 running behind schedule due to fog in the country's northern region.
"Over 20 trains were running behind schedule by several hours and 10 trains have been cancelled today (Monday) morning. Dense fog in northern parts of India affected rail services," a Northern Railway spokesperson said.
Sunday's maximum temperature settled three notches below average at 18.4 degrees Celsius, while the minimum was a notch below average at 6.3 degrees Celsius.