Recently IMD announced the withdrawal of monsoon on 14th October 2019 and other parts of Maharashtra. It is an increasing trend that withdrawal dates are after 10th October. The normal date of withdrawal of monsoon from Mumbai is 1st October.
In 2017 the withdrawal of monsoon delayed by 23 days. It was a rare event where monsoon was withdrawn post Diwali festival.
Though the withdrawal date is 1st October, the data of the past 20 years reveal that the withdrawal dates have surpassed the 06th of October.
Below are some of the statistics of withdrawal dates from the period between 1960 to 2017:
The earliest of monsoon withdrawal: 23rd September 1963
The late monsoon withdrawal: 26th October 2016
1) Number of years in which monsoon withdrew or before 30th September: 8 time
2) Number of years in which monsoon withdrew between 1st to 5th October: 11 time
3) Number of years in which monsoon withdrew between 6th to 10th October: 17 time
4) Number of years in which monsoon withdrew between 11th to 15th October: 17 time
5) Number of years in which monsoon withdrew between 16th to 26th October: 5 time
Hence it can be seen that the maximum number of withdrawal dates are between 6th to 15th October.
Article source: Weatherview.in
Related info: Monsoon rainfall over Mumbai and Onset Dates