Data from the Global Precipitation Measurement or GPM mission core satellite were used to help estimate rainfall data. GPM is a satellite co-managed by both NASA and the Japan Aerospace Exploration Agency.

The city of Chennai on India's southeastern coast was hit particularly hard.  More than 260 deaths have been reported in the Indian state of Tamil Nadu. Data from NASA's Integrated Multi-satellitE Retrievals for GPM (IMERG) were used to estimate the flooding rainfall that fell from November 28 to Dec. 4, 2015.  Over 400 mm (15.7 inches) of rainfall were estimated over areas south of Chennai.

The highest rainfall totals were estimated by IMERG to be over 500 mm (19.7 inches) in an area just of the southeastern coast of India.

The Integrated Multi-satellitE Retrievals for GPM (IMERG) creates a merged precipitation product from the GPM constellation of satellites. These satellites include DMSPs from the U.S. Department of Defense, GCOM-W from the Japan Aerospace Exploration Agency (JAXA), Megha-Tropiques from the Centre National D’etudies Spatiales (CNES) and Indian Space Research Organization (ISRO), NOAA series from the National Oceanic and Atmospheric Administration (NOAA), Suomi-NPP from NOAA-NASA, and MetOps from the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT).  All of the instruments (radiometers) onboard the constellation partners are inter-calibrated with information from the GPM Core Observatory’s GPM Microwave Imager (GMI) and Dual-frequency Precipitation Radar (DPR).