"The Southwest Monsoon has further advanced into remaining parts of West Rajasthan. Thus, it has covered the entire country today, June 26, 2015," the India Meteorological Department (IMD) said in its bulletin.
The normal date for the monsoon to cover entire India is July 15.
"The Southwest Monsoon has covered the entire country. Even the last post of West Rajasthan has been covered entirely.
"In fact, monsoon onset over the region usually happens around July 15, but some good rains in the last 24 hours has led to the declaration of monsoon over West Rajasthan," added Skymet, a private forecasting agency.
The monsoon made a late entry this year as it hit the Kerala coast on June 5 -- a delay of four days from its normal onset date. However, it made speedy progress and has covered the entire country in some 21 days.
Incidentally, IMD has predicted "deficient" rainfall this year.
Meanwhile, Laxman Singh Rathode, the Director General of IMD, said that in 2013, too, the monsoon had covered the entire country before schedule.
So far, from June 1 onwards, the country has received 28 per cent more rain than its normal limit. For the first time in the season, northwest India has recorded 27 per cent more precipitation than normal while central India has so far received 55 per cent more rainfall.
The southern peninsula has witnessed 30 per cent more rain than what it usually receives. Eastern and northeastern India received 3 per cent more rainfall than the normal.
Over the past 24 hours, northwest India has received 469 per cent more rain. While the normal rainfall is 3.2-mm, the region received showers measuring 18.2-mm.
Jammu and Kashmir received a whopping 1,324 per cent more rainfall as the state measured 34.2-mm rainfall in the last 24 hours as against a normal limit of 2.4 mm.
East Rajasthan, where the normal precipitation is 2.6-mm, received 24.6-mm rainfall, marking a 846 per cent increase.
Gujarat region saw 635 per cent more rain while showers were 812 per cent more than the normal in Saurashtra and Kutch.