AbstractGroundwater responses in temperate mountainous terrain are assessed using groundwater, hydrometric and climatic data from southern British Columbia, Canada. Well and stream hydrographs are analysed using a series of diagnostic tools including time series plots, hysteresis plots, and cross‐correlation plots. Characterizing the seasonal timing of the response requires consideration of the hydroclimatology of the region: rainfall‐dominated (pluvial), snowmelt‐dominated (nival) or hybrid (mixture of rain and snow). The magnitude and timing of the recharge and discharge response of the groundwater system was shown to depend on the storage and permeability characteristics of the aquifer and whether the system is stream‐driven or recharge‐driven. These two dominant stream‐aquifer system types were defined based on classifying different aquifer types found in the southwest portion of the province. The classification scheme and diagnostic tools have the potential to provide a framework for evaluating the responses of wells in other mountainous regions. Using this framework, the potential consequences of future climate change may then be better understood based on the interactions between the hydrogeological and hydroclimatic settings of these aquifers. Copyright © 2010 Her Majesty the Queen in right of Canada. Published by John Wiley & Sons. Ltd