Optical wireless communications, which are often referred to as free-space optical communication (FSO), function by sending data across the atmosphere using light. Even while these systems often function well in clear weather, prolonged rain might cause problems and affect their efficiency. Signal Loss and Attenuation: Enhanced Absorption: Raindrops in the atmosphere have the ability to both absorb and scatter optical signals, which causes the transmitted light to be attenuated. Signal Loss: The performance of the link as a whole is impacted by the absorption and scattering of light. Decreased Signal Clarity: Heavy rain produces scintillation, which is characterized by abrupt changes in signal intensity (fading) due to variations in the refractive index of the raindrops. Data transmission may be impacted by this deterioration of the optical signal's quality. Effects on Signal Stability: Beam Misalignment: The light divergence brought on by raindrops can lead to beam misalignment, which calls for changes to keep the connection stable. Differential Attenuation: Rainfall might not be evenly distributed along the link, which could cause differential attenuation and upset the transmitter-to-receiver signal balance. The performance, stability, and signal quality of optical wireless networks are all impacted by severe rain. However, these systems may still deliver dependable communication in inclement weather with careful design, flexible tactics, and routine maintenance.