Abstract. Fiber-reinforced composites (FRC) are becoming increasingly popular in aerospace, automotive and energy sectors. Despite the advantages owed to their strength and lightweight, understanding their behavior in different environments poses challenges. Particularly, humidity, temperature, and freeze-thaw cycles can significantly affect the durability of FRC components. This study investigates the impact of humidity, temperature, and freeze-thaw cycles on FRC inter-laminar areas and the matrix/fiber interface. Experimental methods, including heat analysis, X-Ray tomography and mechanical testing will assess the material's response to changing environmental conditions. This research enhances our understanding of FRC behavior, crucial for designing and maintaining FRC components.