A Sun outage, Sun transit or Sun fade is an interruption in or distortion of geostationary satellite signals caused by interference from solar radiation. The effect is due to the Sun's radiation overwhelming the satellite signal.
In the northern hemisphere, sun outages occur before the March equinox (February, March) and after the September equinox (September and October).
At these times, the apparent path of the Sun across the sky takes it directly behind the line of sight between an earth station and a satellite. The Sun radiates strongly across the entire spectrum, including the microwave frequencies used to communicate with satellites (C band, Ku band, and Kaband), so the Sun swamps the signal from the satellite. The effects of a Sun outage range from partial degradation (increase in the error rate) to total destruction of the signal.