Extensive urbanization is causing a substantial modification of rainfall, posing climate risks to human, environment, and urban systems. Despite increasing attention, the asymmetric impacts of urbanization on different types of rainfall events across climatic gradients remain poorly understood. This study reveals a novel rainfall-type-dependent asymmetry in urban-induced rainfall changes across 19 Chinese urban agglomerations (UAs), spanning humid to arid climates. The results show that the asymmetry is jointly governed by rainfall intensity and duration, with duration emerging as the dominant modulator. Urbanization significantly enhances short-duration rainfall, especially intense events (SDIR) in wetter, warmer, and highly populated UAs, but weakens it in arid ones. In contrast, LDMR (Long-duration moderate rainfall) shows the opposite pattern, with stronger suppression in wetter and warmer UAs but enhancement in arid zones. A weak positive effect on long-duration intense rainfall (LDIR) is observed only in highly urbanized UAs like the Pearl River Delta, Yangtze River Delta, and Beijing-Tianjin-Hebei, implying that a critical threshold of urbanization may be necessary to trigger significant changes in LDIR. These findings underscore the need for tailored urban planning strategies for different regions that consider the urbanization level and climate features to mitigate the increasing risks of climate-related hazards.