ABSTRACT: The Multi-Radar Multi-Sensor (MRMS) system generates an operational suite of derived products in theNational Weather Service useful for real-time monitoring of severe convective weather. One such product generatedby MRMS is the maximum estimated size of hail (MESH) that estimates hail size based on the radar reflectivity propertiesof a storm above the environmental 08C level. The MRMS MESH product is commonly used across the National WeatherService (NWS), including the Storm Prediction Center (SPC), to diagnose the expected hail size in thunderstorms. Previouswork has explored the relationship between the MRMS MESH product and severe hail ($25.4 mm or 1 in.) reported atthe ground. This work provides an hourly climatology of severe MRMS MESH across the contiguous United States from2012 to 2019, including an analysis of how the MESH climatology differs from the severe hail reports climatology. Resultssuggest that the MESH can provide beneficial hail risk information in areas where population density is low. Evidence alsoshows that the MESH can provide potentially beneficial information about severe hail occurrence during the night inlocations that are climatologically favored for upscale convective growth and elevated convection. These findings haveimportant implications for the use of MESH as a verification dataset for SPC probabilistic hail forecasts as well as severeweather watch decisions in areas of higher hail risk but low population density.