Many studies on nitrate (NO₃^-) export from forested catchments have been conducted on temperate forests, but little attention has been paid to the differences in seasonality of NO₃^- export due to differences in climatic conditions, especially in seasonal patterns of precipitation. NO₃^- export in forests in Japan, affected by the Asian monsoon, shows a different seasonal pattern than those in the northeastern United States and northern Europe, where no monsoon occurs. Here, by examining the mechanism by which this difference occurs, the uniqueness of the mechanism of NO₃^- export in catchments in Japan is explored, along with an approach that leads to a more universal understanding of this mechanism. Factors that cause seasonal fluctuations in NO₃^- discharge include the biological conditions responsible for the production of NO₃^- and the hydrological conditions of NO₃^- transport and storage. To address these differences and understand the dynamics fully, a comprehensive database containing descriptions of the seasonality of nitrogen dynamics within a basin and the hydrological process, including soil moisture and groundwater dynamics, is required. In addition, it is necessary to construct process-based models based on the results of meta-analyses using such databases covering multiple climatic zones.