Mumbai has crossed its average seasonal monsoon rainfall quota, with the city’s Santacruz weather station recording 2,442.6 mm of rain from the onset of the southwest monsoon in June until Tuesday morning, September 15.
The rainfall total is about 2% higher than Santacruz’s long-term seasonal average of 2,389 mm for the June-September monsoon period, according to India Meteorological Department (IMD) data.
Mumbai typically receives most of its annual rainfall during the four-month southwest monsoon season. While the suburbs have already crossed their seasonal benchmark, rainfall in the island city has remained below average.
With the Santacruz observatory already recording above-normal seasonal rainfall, Mumbai is heading towards the end of the monsoon with its overall rainfall deficit largely overcome, even as rainfall distribution remains uneven between the suburbs and the island city.
The Colaba observatory has recorded around 1,896 mm of rainfall so far this monsoon, compared with its seasonal average of 2,103 mm. This puts rainfall in the island city division at roughly 90% of its long-term average.
The contrasting figures highlight the uneven distribution of rainfall across Mumbai this season, with the western suburbs receiving significantly more rain than several parts of the island city.
Mumbai experienced a relatively weak spell of rainfall during the first half of September. However, showers intensified over the weekend, bringing substantial rainfall to several parts of the city.
In the 24 hours leading up to Sunday morning, Santacruz recorded 78.7 mm of rain, while Colaba received 40.8 mm.
The increase was particularly sharp when compared with the period between August 31 and September 12. During those 13 days, Santacruz recorded only 51 mm of rainfall, while Colaba received 29.1 mm.
Several areas experienced intense rainfall during the first half of Sunday. Between 10 am and 1 pm, Bandra-Kurla Complex (BKC) recorded the highest rainfall at 147.6 mm. Borivli received 138 mm, while Bandra recorded 135.6 mm. In the eastern suburbs, Chembur also recorded 135.6 mm.
Despite Mumbai eventually crossing its seasonal rainfall average, the monsoon has been marked by considerable fluctuations.
The city recorded a rainfall deficit in both June and August. Mumbai received around 414 mm of rain in June, approximately 25% below the month’s average.
Rainfall was particularly deficient in August, when the city received only about 57% of its normal monthly rainfall.
July, however, brought a dramatic turnaround. Both suburban and island city observatories recorded more than 1,000 mm of rainfall within a single week, helping narrow the cumulative deficit.
Mumbai’s rainfall performance this year also differs from the corresponding period in 2025.
By September 13 last year, Santacruz had recorded 2,625.9 mm of rainfall, equivalent to 113.23% of its seasonal average. Colaba had received 1,700.2 mm, or 81.16% of its seasonal benchmark.
This year, Santacruz crossed its seasonal average later in September, despite the extended dry periods earlier in the monsoon.
Meteorologists expect rainfall activity to ease, with the IMD forecasting light to moderate showers in Mumbai through the weekend. The southwest monsoon is expected to begin its retreat from the region in October.
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