Free Space Optical (FSO) systems are being actively considered as viable options for seamless integration between backhaul optical fiber links and RF or copper links used for last mile connectivity. However, adverse atmospheric conditions can affect the performance and distance over which the link can operate reliably. Propagation of optical waves through the atmosphere is affected by atmospheric turbulence, scattering of aerosols and atmospheric absorption. Atmospheric turbulence is a result of localized variations of temperature, humidity, and pressure in the atmosphere. Turbulence is by nature a random process, and as such may be described using statistical quantities. Atmospheric turbulence induced fading is one of the main impairments affecting Free Space Optics (FSO). FSO systems can suffer outages in the presence of heavy fog, smog and haze. Many places in India see very heavy rainfall. We have studied the effects of rainfall on propagation characteristics in Dakshina Kannada district, Karnataka, India where Surathkal is located which is affected by heavy rainfall for about four to six months in a year. We observe that the attenuation during heavy rainfall is quite high and leads to extremely low levels of the received signal or complete erasure of the transmitted data. With the validation through simulation in this paper, on the use of Digital Fountain codes in FSO links, we suggest that if such codes are used in areas prone to rainfall, it would help in the recovery of dropped packets and would also improve the BER performance.