Hail and tornadoes are hazardous weather events that are responsible for significant property damage and economic loss world-wide. The most devastating hail and tornado events are commonly produced by supercells in the United States. However, some hazard-producing supercells may grow upscale into mesoscale convective systems (MCSs) or may be embedded in MCSs. Quantifying the relationship of hail and tornado occurrences with MCSs which have large spatial (over 100 km) and temporal scales (over 10 hours) has important implications in understanding the predictability of weather hazards at the medium-range forecasts (i.e., subseasonal to seasonal scales), but such studies are lacking. In this work, the radar-defined MCSs (convective systems with large, contiguous radar reflectivity coverage) are extracted from a recently developed 14-year MCS tracking database over the contiguous United States. By matching the concurrent hazard reports to the extracted MCS convective features, we analyze the characteristics of hail and tornadoes associated with MCS vs. non-MCS including the seasonal and regional variability and morphology of the systems. Key findings will be presented and physical interpretations of the results will be discussed.