Runoff variability in mountainous basins is influenced by complex precipitation–snow–temperature processes, and the timing of water release from snow storage can play an important role in streamflow generation. The Haraz River Basin, characterized by high-elevation areas and partial dependence of its runoff on snow storage, provides a suitable setting for investigating these processes. In this study, a 10-year time series of hydro-climatic and runoff variables was analyzed to identify seasonal and spatial patterns and determine the factors influencing streamflow in the Haraz River Basin. Relationships among precipitation, temperature, snow water equivalent (SWE), and different runoff components were examined using Pearson correlation and lagged analyses, followed by the assessment of the simultaneous effects of the variables using multiple linear regression. The mean total runoff was 488.26 mm, with subsurface runoff accounting for a larger contribution (293.77 mm) than surface runoff (194.49 mm). Precipitation and temperature showed correlation coefficients of 0.473 and 0.467, respectively, with total runoff, whereas the simultaneous correlation between SWE and runoff was only 0.072, increasing to 0.73 at a two-month lag. Subsequently, multiple linear regression was employed to simultaneously evaluate the contribution of the hydro-climatic variables, explaining 58% of the variability in total runoff, with RMSE, NSE, and Bias values of 206 mm, 0.58, and 0, respectively. The results indicate that the timing of snow-storage release, together with precipitation, is a key factor regulating runoff in the Haraz Basin. Incorporating this temporal lag can improve the assessment and prediction of water resources in the basin.