The Dry Andes is a critical water resource for downstream regions, yet groundwater recharge processes remain poorly understood. These environments are characterized by low precipitation, sparse vegetation, and seasonally frozen ground overlying deeper, dry permafrost. Freeze–thaw dynamics in the shallow subsurface can strongly regulate infiltration and groundwater recharge timing. Our research focuses on the De Los Mogotes River basin in the Dry Andes of northern Argentina (4,218–5,664 masl), where two monitoring sites are instrumented with temperature and moisture sensors to depths of 3 m. Although deeper permafrost is inferred from regional evidence, our simulations target supra-permafrost groundwater processes, including the active layer. The Simultaneous Heat And Water (SHAW) model is used to simulate coupled soil temperature and moisture dynamics, snow accumulation and melt, and vertical water fluxes. Observed soil temperature records indicate limited near-surface freezing at the monitoring sites during winter, with temperatures at 1 m depth remaining below 0 °C for approximately 73 days per year, with minimum values above −1 °C. Sensors at 2 and 3 m depths remain above freezing throughout the winter. Model results suggest that approximately 60–70% of infiltrated water reached the 2.5 m boundary. The model does not account for lateral subsurface flow, which may be non-negligible in steep terrain and could overestimate vertical recharge. By constraining shallow thermal and hydrological processes above permafrost, our research provides a process-based foundation for linking near-surface recharge mechanisms to deeper groundwater systems and improves the assessment of water resilience in arid, high-mountain environments.