The early onset of monsoon and steady downpour has ensured that the city is not too far from reaching its quota of rain for this season.
Within 50 days of rains, the city has received more than 70% of its annual average rainfall in both south Mumbai and suburbs.
Colaba, which receives 2,200mm average rainfall annually, had received 1,732.2mm rain till 8.30am on Wednesday, while Santacruz, which records 2,598mm of average rainfall annually, had received 1,900.1mm.
Thus south Mumbai has received 78.73% of the average annual rain and Santacruz has received 73.13% of average annual rainfall this year.
Tuesday’s heavy downpour broke another record for singleday rainfall.
The 218.6mm of rain recorded at Colaba between Tuesday 8.30am and Wednesday 8.30am was the second highest in a decade, only behind 249.
7mm recorded in 2008. Santacruz, meanwhile, recorded 215.6mm rain in the same time.
The Met department said frequent low-pressure systems over the Bay of Bengal were driving a lot of the rainfall witnessed in central as well as coastal Maharashtra, including Greater Mumbai.
A low-pressure area is when the air pressure in a given area is lower than the surrounding air.
In a low-pressure system, the air rises and when it reaches high altitudes, the humidity condenses into rain.
The cloud cover moving from the eastern side halts around the Western Ghats, bringing in heavy rain to Mumbai.
“The western coast has received sizeable rain this year due to the pressure systems over Bay of Bengal. Usually the trough over Arabian Sea is more influential in getting rains for this coast, but a better frequency of monsoon system formation has resulted in surplus rainfall. Coupled with the low-pressure systems, the offshore trough on west coast draws in a lot of moisture,” said NY Apte, deputy director-general, India Meteorological Department, western region.