Climatic conditions, such as hail, strongly affect the efficiency of photovoltaic (PV) modules. The aim of this paper is to present comprehensive analytical and experimental research results and to evaluate the impact of hail on PV modules. The experimental study was conducted using a new approach in hail simulation testing the impact on PV modules. The impact of hail was compared using mechanical parameters, which were in turn reflected by electric power produced by a PV module. Based on both simulation and experimental results, optimization guidelines were proposed to improve mechanical resistance of PV modules. The scientific novelty of the article is the optimization of the theoretical model of the PV element based on experimental data. Mechanical impact parameters in PV modules, such as force transmission and final stress, decreased from 236 kN/m2 to 109.8 kN/m2 during the optimization process (geometry packages to obtain the lowest stresses).