Monsoon Onset Over Mumbai

The Southwest Monsoon officially advanced over Mumbai, 23rd June 2026, bringing widespread rainfall, gusty winds, cloudy skies, and much-needed relief from the prolonged heat and humidity. The onset comes nearly two weeks later than the normal arrival date which is around 10 June, marking one of the delayed monsoon onsets over Mumbai in recent years.

This year, the monsoon made an early onset over Kerala but thereafter witnessed a prolonged pause in its northward advance, especially along the Arabian Sea branch. After crossing Kerala, the progress slowed considerably due to the absence of strong synoptic support over the Arabian Sea and western coast.

In 2025 Monsoon recorded earliest onset over Mumbai on 26th May.

In 2024 Monsoon set over Mumbai on 06th June 2024. In 2023 it was set late on 25th June 2023. 

Being the coastal city and due to Sahyadri mountains, Mumbai receives good amount of rainfall over 2000 mm durng monsoon as compared to 500mm over other places in interior Maharashtra.

Here are some facts about rainfall during the period of June to September.

The normal date of monsoon over Mumbai was 10th June, but the dates had been fluctuating. In some years the monsoon was delayed considerably while in some years it had been very early.

Here are some statistics for onset dates over Mumbai:
1) Early onset – 25th May 2025 and then 29th May in the year 1952, 1956, 1872
2) Late onset  – 25th June in 1959, 2019, 2023

Monsoon onset dates since 2010:

The average seasonal rain that is rainfall from June to September is:

1) Santacruz is 2265 mm.

2) Colaba is 2025 mm.

The extreme rainfall events in Mumbai:

Colaba	10 June 1991 478 mm	5 July 1974 576 mm	3 Aug 1881 287 mm	10 Sept 1930 548 mm
Santacruz	10 June 1991 399 mm	27 July 2005 944 mm	23 Aug 1997 346 mm	23 Set 1981 318 mm

For detailed rainfall statistics over Mumbai visit: IMD Mumbai website