Mesoscale Convective Systems (MCS) are common over Europe and can produce severe weather, including extreme precipitation, which can lead to flash floods. The few studies analyzing the climatological characteristics of MCS over Europe are either based on only few years of data or focus on limited sub-areas. Using the recent Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) satellite precipitation climatology, we identify and track MCS for 16 years over Europe. We devise a spatial filter and track cells according to the overlap of filtered rain patches between consecutive time steps. By fitting an ellipse to these patches, we determine their overall shape and orientation. To distinguish convective rain patches we condition on lightning data, thus reducing potential identification errors. We analyze this new European MCS climatology to characterize MCS rainfall properties: MCS overall occur most frequently over the Mediterranean and Atlantic during fall and winter, whereas during summer, they concentrate over the continent. Typically, more than half of seasonal precipitation can be attributed to MCS, and their contribution to extreme precipitation is even greater, often exceeding 70\%. MCS over the continent display a clear diurnal cycle peaking during the afternoon, and some continental areas even show a second, nocturnal peak. The MCS diurnal cycle for coastal and oceanic regions is more variable. Selecting sub-areas, we find that the spatio-temporal distribution of MCS precipitation throughout the year can be well explained by the spatio-temporal distribution of specific environmental variables, namely (sea) surface temperature, fronts occurrence and convective instability.