Facts About Monsoon Onset & Rainfall Over Mumbai

On 12th June 2017, Monsoon is set over Mumbai, 2 days after it’s normal date. There is no definite pattern of monsoon to progress, which is evident from the fact that monsoon set 2 days prior in Kerala.

Now since Mumbai is ready to take up monsoon here are some facts about rainfall during the period of June to September.

The normal date of monsoon over Mumbai is 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 – 29th May in the year 1952, 1956, 1872
2) Late onset  – 25th June in 1962

Below is the chart of monsoon dates over Mumbai for last 67 years. (Data source: IMD)

(Click the image to see enlarge image)

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