A multi-scale modelling strategy is proposed to investigate the potential effects of hygrothermal ageing on the ballistic performance of CFRP laminates. At the micro-scale, damage evolution due to cyclic hygrothermal loads is simulated on a representative microstructure using an adapted fatigue damage law. Then, the results of the micro-mechanical analysis are used to measure the predicted transverse crack density and calibrate a meso-scale material model with the effects of micro-scale damage. Finally, a meso-scale impact model is generated with seeded transverse cracks at the predicted crack density and the calibrated material properties from the homogenisation step, which allows for the performance of the laminate to be compared at different stages of hygrothermal ageing damage.