A cloud cover across Delhi and the National Capital Region (NCR) since Wednesday morning brought down the temperature at least two degrees Celsius lower compared to Tuesday.
"Conditions have become favourable on Wednesday for the advancement of the monsoon to the Delhi-NCR region," IMD regional head Kuldeep Srivastava told .
"The wind direction has changed from westerly to easterly. Light rainfall is expected over the area in the next 48 hours. A drizzle can be expected in some parts of Delhi-NCR on Wednesday," he said.
According to IMD, flow of humid winds from the Bay of Bengal has increased moisture in the air which would lead to one or two short spells of thunder activity and light rains in parts of the region from Thursday.
Private weather forecasting agency Skymet told that the intensity of thunder activities were likely to increase on July 5 and 6.
"However, the actual onset of monsoon is likely to be only on July 6," said Skymet chief meteorologist Mahesh Palawat.
A bulletin released by the IMD on Wednesday morning said that the southwest monsoon had further advanced into parts of East Rajasthan, most parts of Madhya Pradesh, remaining parts of Chhattisgarh, some more parts of Uttar Pradesh, most parts of Uttarakhand as well as some parts of Himachal Pradesh and Jammu and Kashmir.
Monsoon normally hits Delhi by June 29. This year, its onset has been delayed by a week.
( With inputs from IANS )