MSc thesis focusing on stream temperature research in a subarctic catchment. / Water temperature is an important stream characteristic that has a significant impact on the biological and chemical processes within an aquatic ecosystem, and it is sensitive to changes in climate and hydrologic regimes. Stream temperature dynamics are driven by heat exchange processes with the atmosphere and the interaction between surface water and groundwater, and it is uncertain how thermal regimes in northern environments will change under a warming climate. The objective of this thesis is to evaluate summer stream temperature variability in the Wolf Creek Research Basin (WCRB), and investigate relationships between stream temperature and hydrometeorological variables. Long-term stream temperature data for the WCRB in Yukon Territory, Canada was collected from 2002 to 2019 at both the outlet of Wolf Creek (WC), and for one of its high-elevation tributaries, Granger Creek (GC). Linear regression models were developed to explore relationships between stream temperature and various predictor variables at monthly and seasonal scales. The incorporation of an autoregressive term into regression models determined the importance of accounting for the autocorrelation structure of daily measurements, when considering annual regression coefficients. Model selection identified air temperature as the primary predictor variable for daily stream temperature, with streamflow and precipitation having variable inter-annual influences. Monthly stream temperatures at Granger Creek were related to air temperature, date of snow disappearance and antecedent stream temperature, whereas Wolf Creek monthly stream temperatures were most strongly related to antecedent stream temperature. These results suggest that the timing of snowmelt, streamflow, catchment thermal memory (as represented by antecedent stream temperature), and seasonal meteorology interact to influence interannual variability in summer stream temperature at the Wolf Creek Research Basin. / Thesis / Master of Science (MSc) / Water temperature plays an important role in determining the quality of an aquatic environment. There are many factors that control stream temperature, and it is uncertain how temperatures in northern environments will respond in the future. The objective of this thesis is to evaluate influences on summer stream temperature in the Wolf Creek Research Basin (WCRB). Stream temperature data was collected for the WCRB in Yukon Territory, from 2002 to 2019 for both Wolf Creek (WC) and Granger Creek (GC). Air temperature had the strongest relationship with daily stream temperature; streamflow and rain had inconsistent relationships through time. Monthly stream temperatures at Granger Creek were related to air temperature, date of snow disappearance and prior month’s stream temperature. Wolf Creek monthly stream temperatures were most strongly related to prior month’s stream temperature. These results highlight underlying influences on stream temperature, which may not be captured by a stream temperature models.