The Second Research Coordination Meeting on Understanding the Importance of Convective Rain Events and Tracing Their Impact on the Catchment with Isotopes will bring together the participants on the CRP F31007 to present the achievements of their individual projects so far (Day 1), linking the projects in a common data base and through joined publications and guidelines (Day 2), technical training on sampling precipitation and groundwater for analysis of sulfur-35 (Day 3), planning next activities and presentation of outcomes (Day 4). Regarding the training on Day 3, it should be mentioned that the IHS developed a pre-concentration method for sulfur-35 in the field that is meant to improve access of MS to this important tracer for groundwater vulnerability. Part of the CRP is to test the applicability to a wide range of geographic locations. The second RCM will include an in-person training on the IAEA sampling method for sulfur-35, so that CRP participants can send their samples to the IHL or analyse them in their laboratory where a LSC is available. The data base that can be achieved through this effort will include the first data on sulfur-35 in precipitation from the tropics and the southern hemisphere and a proof-of-concept of the method developed at the IHL.