Rain fade is an interruption of wireless communication signals as a result of rain or snow droplets whose separation approximates the signal wavelengths. The phenomenon can affect satellite Internet connections as well as satellite television and other systems.
Most satellite communication takes place in the microwave portion of the electromagnetic radiation spectrum. Signals at these wavelengths, typically on the order of a few inches, are affected by heavy concentrations of water droplets or ice crystals in the atmosphere. When the mean distance between water droplets or crystals is comparable to the wavelength of the electromagnetic signals, severe attenuation can occur. The observed effect is a degradation or loss of communications during heavy downpours, snow squalls, and blizzards.
Rain fade usually does not last long. Once a heavy shower or squall has passed, normal communications returns. However, during tropical storms or severe winter storms at northern latitudes, fadeouts can persist for hours at a time. The phenomenon occurs with all types of satellite systems, including geostationary (GEO), low-earth-orbit (LEO), and medium-earth-orbit (MEO). It can also affect the Global Positioning System (GPS).
Compare solar fade.