The study combines dendrochronology and the Vaganov-Shashkin process model to systematically analyze the climate response mechanisms of radial growth in Pinus armandii and Pinus tabuliformis at the southern foothills of the Qinling Mountains at annual, monthly, and daily scales. It also integrated with four CMIP6 scenarios (SSP126, SSP245, SSP370, SSP585) to predict their future adaptability, providing a basis for the sustainable development of forests. The results showed: (1) With a continuous increase in temperature (P < 0.05) in the study area, Pinus armandii in the Huoditang Forest District showed a significant upward growth trend from 1971—2023 (Slope = 0.003, P < 0.05), while Pinus tabuliformis in Wuxiang Forest District slowed down its decline by responding to the sudden change in temperature. (2) The responses of the two species showed spatial-interspecific divergence: Pinus tabuliformis in the Wuxiang Forest District responded positively (P < 0.05) to the air temperature in October of the previous year and March and September of the current year, but was suppressed by precipitation in September of the previous and current year, while Pinus tabuliformis in Huoditang Forest District responded positively to the air temperature in April-August of the current year, and negatively to the precipitation in August and October of the previous year. The differences in response patterns of Pinus armandii were even more significant: Pinus armandii in Wuxiang Forest District was negatively regulated by the temperature in June of the previous year and precipitation in February and September of the current year, while Pinus armandii in Huoditang Forest District responded significantly positively (P < 0.05) to precipitation in September of the current year. (3) The Vaganov-Shashkin model indicated that Pinus armandii and Pinus tabuliformis were continuously limited by precipitation during the May-September growing season, that increasing temperatures resulted in a longer growing season for both, and that Pinus armandii in Wuxiang Forest District significantly lengthened the growing season by efficiently mitigating water stress through improved drainage (0.33 days/year, P < 0.05). (4) Under future scenarios, the tree ring index of Pinus armandii is projected to increase by 4% (P < 0.05) by 2064, with its lower water demand threshold (W1 = 0.0079%) outperforming that of Pinus tabuliformis (W1 = 0.0397%), demonstrating superior adaptability to warming-drying conditions. This study provides a physiological process-based decision-making tool for the Qinling Mountains planted forests to cope with warming-drying trends and to achieve carbon peaking and carbon neutrality goals. It can be used as a reference for studying tree species adaptation in similar climatic zones.