Reinforced concrete (RC) structures in cold and arid regions are simultaneously subjected to wind-sand erosion and freeze-thaw cycles, resulting in complex deterioration of their mechanical performance. To investigate this coupled effect, a series of laboratory tests were conducted on FRP-confined RC columns under controlled environmental conditions, including wind-sand erosion at a velocity of 26 m/s and freeze-thaw cycles ranging from -20 degrees C to +20 degrees C up to 200 cycles. The experimental results indicate that plain concrete specimens exhibit significant degradation, with reductions of 32.4% in compressive strength and 36.7% in flexural strength after 200 cycles. In contrast, specimens confined with CFRP, GFRP, and BFRP retain 87.2%, 84.6%, and 82.1% of their initial mechanical properties, respectively, demonstrating the effectiveness of FRP confinement in mitigating environmental damage. Based on the observed behavior, the damage evolution mechanisms under coupled wind-sand erosion and freeze-thaw actions are systematically analyzed. Wind-sand erosion increases surface permeability and facilitates moisture ingress, while freeze-thaw cycles induce internal microcracking and reduce material cohesion. The interaction between these processes forms a positive feedback mechanism that accelerates structural deterioration. Although FRP confinement restrains lateral expansion, it cannot prevent the accumulation of internal damage, leading to interfacial debonding, local bulging, and eventual rupture. Furthermore, a unified multi-parameter empirical model is proposed to quantitatively predict the degradation behavior of FRP-confined RC columns by incorporating the effects of freeze-thaw cycles, erosion intensity, and confinement characteristics. The proposed model shows good agreement with the experimental results, with the coefficient of determination (R 2) ranging from 0.9126 to 0.9413 for all specimens, indicating high predictive accuracy and robustness. Finally, this paper presents engineering design recommendations for FRP-reinforced concrete columns under various environmental conditions.