Eutrophication due to excessive phosphorus (P) loads to inland waters is a major challenge worldwide. While quantification and management of P loads from agricultural areas has been well studied over the past decades, non-point source P loading from urban areas is less well understood. It remains unclear how P exports vary between different urban land use types and between seasons. The objective of this study is to evaluate P exports from a cold climate urban watershed, including the effects of land use and seasonal variability. The objective was addressed by event-based field monitoring during summer and fall seasons over a 29-month period within a 5.8-km2 watershed in London, Ontario. This was combined with load estimations calculated using LOADEST, and the development and calibration of a hydrologic and water quality (SWMM) model. Water quantity and quality data, including total suspended solids (TSS) and total P (TP) were collected at two watershed outlets representing different land use areas. Field data indicate that TP concentrations at the watershed outlets consistently exceeded the eutrophic threshold of 30 µg/L during baseflow and event flow conditions. LOADEST estimations highlight the large contribution of individual extreme precipitation events to total annual P loads. The calibrated SWMM model simulated monthly TSS and TP loads that were consistent with the LOADEST estimations. This SWMM model can now be used as a valuable tool for simulating the impact of future land use, stormwater management and climate change scenarios.