Similar to Jupiter’s Great Red Spot, a white spot on Saturn reveals the presence of a huge atmospheric storm.
Unlike Jupiter’s ever-present spot, Saturn’s white spot appears only periodically, approximately every 30 years.
First identified in 1876, the spot has appeared more or less on schedule ever since.
It is located near the equator and can be seen for several months at a time.
Previous Great White Spots were observed in 1876, 1903, 1933, and 1960, with the 1933 storm being the most famous.
It is predicted that another storm on Saturn will occur in about 2020.