Thanks to dry winds from Rajasthan and Pakistan, the temperature in Delhi surpassed the previous highest of 47.8 degree Celsius which was recorded on June 9,2014.
The Palam observatory of the Indian Meteorological Department (IMD) recorded the temperature of 48 degree Celsius after 3 p.m., an official of the state-run weather forecaster said.
"Today was the hottest ever day in the history of Delhi," the official added.
The IMD's observatory in Safdarjung, however, recorded the maximum temperature at 45.6 degrees Celsius.
According to private forecaster Skymet, absence of rains over the past two weeks and dry westerly winds led the temperature to soar substantially on Monday.
"There has been no pre-monsoon activity in the past two weeks. So no rains. Also, westerly dry winds from Pakistan and Rajasthan contributed to intensifying the heatwave situation," Skymet Director Mahesh Palawat said.
Western, central, and northern parts of the country on Monday witnessed a surge in temperature, making the heatwave conditions severe.
However, the situation is expected to ease from Tuesday as the monsoon is likely to make progress, though it is expected to reach Delhi only in the first week of July.
There are chances of rains in the national capital and parts of the northern India on Tuesday evening, which will bring down the soaring mercury.
"There is a cyclonic circulation in the Arabian Sea while one is being formed over Rajasthan. It will cause rains in Delhi for two-three days," Palawat said.
Heatwave conditions are set to die down now with the arrival of monsoon as westerly winds will stop and easterly winds filled with moisture will come to the northern region.
"There will be an increase in humidity but the temperature will not cross 40-43 degree," Palawat said.
( With inputs from IANS )