Paleoclimatic reconstruction in the hyper-arid southern Negev is challenging due to limited proxies. Under such arid conditions, soils typically accumulate halite and gypsum rather than CaCO3. Previous studies have identified CaCO3 cementation within active channel alluvium, as well as in terrace outcrops. Paleoclimatic interpretation of such deposits has been held back by uncertain formation temperatures and the difficulty of distinguishing between water sources and evaporation intensity signals. Here, we measured δ13C, δ18O, and clumped isotope composition (Δ638) in 16 samples derived from laminated carbonate cement in a > 450 ka alluvial terrace in the Shehoret catchment. Clumped isotope derived cementation temperatures were used to calculate precipitating water δ18O. Additionally, modern temperatures within alluvial fill were monitored at depths of 15-90 cm to serve as a modern baseline. All samples present the most depleted stable isotopic values observed in the southern Negev, with δ13C values of -3.4‰ to -0.7‰ and δ18O values of -10.5‰ to -5.8‰. Depleted δ13C values suggest slightly enhanced plant activity relative to modern conditions. Cementation temperatures (23.6±4.9°C to 31±5.5°C) fall within the range of modern temperatures at the carbonate formation depths, between 19.5°C and 38.8°C. Calculated precipitating water δ18O values range from -7.5±1.4‰ to -3.2±1.4‰, more depleted than modern southern Negev precipitation (-3.1‰ to +3.3‰), and well within the northern and central Negev ranges (-9.5‰ to -1.8‰). Depleted δ18O values, warm cementation temperatures, and laminated cement texture indicate that precipitation occurred in a cyclic pattern of heavier rainfall, rapid infiltration, and minimal evaporation compared to modern conditions, followed by carbonate cementation under higher temperatures. Specific cementation ages (in progress) will determine whether these conditions occurred during glacial or interglacial stages, providing additional constraints to the hypothesis of increased interglacial moisture in the Negev during the Quaternary.