Stormwater is known to transport urban pollutants into the aquatic environments. Pesticides are one of the important groups of organic pollutants associated with urban land use that impose significant risks to ecosystem health. Previous studies of pesticide occurrence in U.S. surface waters suggest that urban streams have shared pesticides “signatures”; however, few studies have directly measured the pesticide concentrations in storm sewer discharge. In this project, we collected samples directly from the storm sewers in two different municipalities in Western New York and monitored pesticide concentrations as well as a suite of water quality parameters. Overall, the detection of pesticides in our stormwater samples was less frequent and at lower levels than expected from the previous surveys of surface waters in the Northeast region, suggesting a dependence on the specific storm sewershed. The highest pesticide concentrations were detected in a summer storm after a long dry period. The extensive water quality analyses allowed us to examine the possible pollutant transport pathways. In most storms, both dissolved organic matter (indicated by dissolved organic carbon) and particulate matter (indicated by turbidity) showed higher levels at the initial stage of the storm. In comparison, the characteristics of the dissolved organic matter (indicated by specific UV absorbance at 254 nm and fluorescence excitation-emission matrices) remained relatively stable throughout the storm. Unique weather events such as the 2023 summer wildfires led to distinct stormwater quality such as elevated levels of dissolved organic carbon and inorganic nitrogen species. The finding of this study illustrated the dynamic nature of urban stormwater and highlighted the needs to assess stormwater quality over temporal and spatial scales.