4 min readMumbaiJun 1, 2025 07:08 PM IST
First published on: Jun 1, 2025 at 07:08 PM IST
With record-shattering downpour sweeping the region in May, Mumbai city district has logged excess rainfall of over 3025 per cent of its actual average rainfall for the season, making it Maharashtra’s wettest district until May.
Meanwhile, the Santacruz station has recorded an excess rainfall by 1945 per cent.
Overall, Maharashtra recorded “large excess” rainfall by 560 per cent until May.
In what made for an unusual summer, heatwaves and above normal temperatures eluded the city in May as it started receiving unseasonal showers, followed by pre-monsoon rain, as early as May 6.
After intermittent spells of moderate showers, Mumbai experienced its earliest onset of southwest monsoon in the past 75 years as torrential rainfall battered the city on May 26.
Spurred by unseasonal showers and early onset of monsoon, records from the India Meteorological Department (IMD) show that Mumbai city district has recorded “large excess” in showers by 3,025 percent while the suburban district has recorded above normal rainfall by over 1,945 percent.
According to the data, the IMD’s Colaba station in island city received 503.2 mm rainfall in May, as against its average of 16.1 mm rain from March to May.
Meanwhile, the Santacruz observatory in Mumbai suburbs received 378.4 mm rainfall, marking a significant departure from its actual average of 18.5 mm rain for the period.
For the record, this has been the wettest May month ever recorded in Colaba since 1918 while also being Santacruz’ rainiest May in the past 25 years.
Not just Mumbai, but the entire Maharashtra has recorded an excess of 560 per cent from its actual long-period average (LPA) until May 31.
While the state typically receives an average of 26 mm rain during the months of March to May, it has recorded an average of 170.3 mm rainfall until May 31.
Besides Konkan region, district-wise rain data from the IMD show that Madhya Maharashtra region has recorded an excess in showers by 457 per cent so far, while Vidarbha belt has registered excess downpour of over 481 per cent. Meanwhile, the region of Marathwada has recorded an excess of 394 per cent so far.
Meteorologists have attributed the heavy showers to a combination of favourable factors ranging from an upper-level trough that ushered in heavy rain early in May to a low pressure area which developed into a well-marked LPA in the Arabian Sea after May 20.
Furthermore, senior IMD scientists have also pointed to active Madden-Julian Oscillation (MJO) as well as the neutral El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) conditions as factors contributing to an early onset.
Above normal rain in June: IMD
After rainy May, the IMD has said that the city, as well as other parts of the country, will continue to receive “above normal” rainfall in June. The above normal rain will also usher in a dip in temperatures which are likely to remain in the normal to below normal range across the region.
Typically, Mumbai receives an average of 537 millimetres of rainfall in June, during which it experiences monsoon onset.
On Sunday, the city and its neighbouring districts woke up to brief spells of moderate showers amid a nowcast warning sounded by the IMD at 10 am, followed by another warning at 1 pm.
According to the IMD, the city will continue to experience light to moderate rainfall in the coming days with the showers slated to intensify and be accompanied by thunderstorms, from June 5.
While no alerts have been issued for Mumbai, a fresh yellow alert stating the likelihood of ‘thunderstorms with moderate rain and gusty winds’ has been sounded in Thane for June 5.
In what made for an unusual summer, heatwaves and above normal temperatures eluded Mumbai in May as it started receiving unseasonal showers, followed by pre-monsoon rain, as early as May 6. (File Photo/Sankhadeep Banerjee) 
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