In order to understand typical monsoon rainfall pattern, a model has been developed by analyses of continuous hourly rainfall dataset from year 1997 to 2013 of a coastal site of India, which pre-dominantly receives the south west monsoon. The site receives nearly 90% of its annual rainfall in four months (June to September) on average 90 rainfall days. The analysis shows that the maximum number of rainfall events is limited to up to 8 hours, thereby, confirming the deluge/torrential pattern of a tropical rainfall. Also, maximum 1-hourly to daily rainfall ratio have been studied to derive a conservative design basis for typical monsoon rainfall. Since rainfall data in the country is available primarily on daily (24-hourly) basis and not on continuous basis, this would serve as a general design basis of other places where such continuous record is not available.

Keywords: Monsoon, 1-hourly rainfall, 24-hourly rainfall, Deluge.