The cloud pattern on Jupiter is the visible system of colored cloud tops in the atmosphere of the planet Jupiter, remarkable for its stability. Astronomers have given names to parts of this pattern, using the word zone for the light stripes and belt for the dark stripes along various latitudes. The pattern and intensity of its belts and zones are famously variable, often changing markedly from one opposition to the next.
The normal pattern of bands and zones is sometimes disrupted for a period of time, in events that astronomers call "disturbances". The longest-lived disturbance in recorded history was a "Southern Tropical Disturbance" (STropD) from 1901 until 1939, discovered by Percy B. Molesworth on February 28, 1901. It created a darkened feature over a range of longitudes in the normally bright Southern Tropical zone.