The normal onset date for south-west monsoon in the capital is June 29 but the phenomenon had reached the city ahead of schedule on June 26 last year.
The Weatherman predicts that the monsoon is likely to touch the capital in the second half of next week.
The city has been reeling under heat wave conditions for almost the whole month and barring a few days, the maximum remained over 40 degrees Celsius, prompting people to wish for early rains.
The maximum in the city today was recorded at 42 degrees Celsius, six degrees above normal, while the minimum was at 31.6 degrees, four degrees above normal.
"There was a hiatus in the advance of the monsoon mainly due to northward shift of the heat trough towards the foothills of Himalayas and non-formation of any strong weather system in Bay of Bengal," an official statement said.
The analysis of current meteorological conditions indicate increase in rainfall activity over east, central and also over northwest India due to development of seasonal east-west trough with embedded upper air cyclonic circulation in the coming days.
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"Conditions would thus become favourable for further advance of monsoon over some more parts of central India and northwest India mainly during second half of the week," the statement said.
Though it came three days earlier last year, the monsoon had a late arrival in 2010. The seasonal rains started only on July five in 2010.
The earliest onset of monsoon over Delhi during the past 30 years was on June 15, 2008 and while the most delayed onset was on July 26, 1987.
During monsoon, Weatherman says, if the city gets 645.7 mm of rains, it is considered normal the capital.