Composite materials find extensive applications in numerous fields, including mechanical components, which are often subjected to varying climatic conditions. Due to the contrasting conditions, there is a difference in the external loadings, leading to the transfer of air, heat, and moisture between the environments. Here, the study is done to model the moisture-based diffusion in order to predict the output beforehand so that necessary precautions can be taken before it fails. The study primarily investigates the heat and moisture-based absorption behavior of composite materials. The Representative Volume Element (RVE) approach is chosen, which enables the simulation of the behavior of the composite at a microscale level, giving insights into the micromechanics and analyzing the material absorption behavior of moisture. The FEA approach for the same is carried out using the COMSOL Multiphysics software. The required RVE of the composite is modeled, and the effect of fiber volume fraction on the hygroscopic swelling, followed by the effect on its properties, is derived. Subsequently, the mechanical characterization of the material is performed. The composite model is run through a moisture-based environmental condition, as in the previous case to evaluate the effects of moisture on the strength of the composite material. The material exposed to the moisture environment showed water uptake. The increase in water uptake causes a decrease in the strength of the material compared to the material with no exposure to moisture. The study focuses on the relationship between the composite’s moisture content and its mechanical characteristics, which can be helpful for the responsible modeling of components in the required environment.