The interaction between sea and climate in the scientific literature about the Mediterranean has changed during the twentieth century. In fact, a perceptual shift is observed if we delve into the different climatic classifications of the Mediterranean defined by climatologists and geographers. This study reviews the most important indices derived from the history of Mediterranean climatology, offering four maps that help visualize the evolution of conceptions of the Mediterranean climate. It also proposes a new index based on tritium isotope concentration. The paper argues that there is a paradigm shift from a “static” towards a “three-dimensional and dynamic” perspective of the Mediterranean Sea. The State Meteorological Agency (AEMET), the Agroclimatic Information System for Irrigation (SIAR), the Portuguese Institute for Marine and Atmospheric Research (IPMA) and the Network of Automatic Meteorological Stations in Catalonia (XEMA) provide meteorological data (temperature, rainfall, evapotranspiration, and atmospheric pressure) which we have used as inputs for four different indices. We have retrieved REVIP records for the period 2000–2021 to study the spatial distribution of long-term precipitation. Finally, we have correlated the REVIP dataset with the North Atlantic Oscillation Index (NAOi) and the Western Mediterranean Oscillation Index (WeMOi). Our methodology consists of two steps: (1) collecting data from various previously cited sources and applying a SWOT matrix to analyze each Mediterranean climate index; (2) showing how the isotopic signature of precipitation could function as a valuable tool for understanding the entire hydrological cycle, encompassing the Mediterranean Sea as a water body. The REVIP dataset could be serve as a valuable tool for tracking the origin, evolution and historical aspects hydrological cycle, as well as for developing new Mediterranean climate indices from a three-dimensional perspective, i.e., incorporating the Mediterranean Sea in the climate system. However, further research is required to determine whether the isotopic signature is influenced by atmospheric processes, such as those associated with torrential rainfall, or if it is the influenced by local or regional characteristics of the Mediterranean Sea.