Deep moist convection produces several hazards including downbursts, tornadoes, large hail, and short-duration precipitation extremes, resulting in fatalities and substantial economic losses. This study employs observational reports, lightning flashes and the ERA5 reanalysis over Spain (2015–2024) to summarize the key environmental differences between non-severe convection and each of these hazards, by ranking 203 convective parameters according to their discriminatory skill, and comparing composite vertical profiles. Summer downburst environments are markedly warmer than non-severe environments, with downdraft Convective Available Potential Energy (CAPE) emerging as the most discriminating parameter. Non-summer downbursts show enhanced wind shear relative to non-severe convection, though rarely reaching High-Shear–Low-CAPE conditions. Summer tornadoes and waterspouts display higher 0–3 km CAPE and a lower level of free convection than non-severe convection, but non-summer cases overlap substantially with non-severe environments. Hail over 5 cm in diameter occurs mostly in summer, in environments of elevated CAPE and shear, best distinguished by the WMAXSHEAR composite index. Short-duration precipitation extremes, evaluated during non-summer months, are associated with elevated moisture and some supercell signatures, supporting slow motions. These results provide a comprehensive framework for future studies on severe convective weather and climate model projections, representative of the Mediterranean severe convective environments.