Climate One difference between Neptune and Uranus is the typical level of meteorological activity. When the Voyager 2 spacecraft flew by Uranus in 1986, that planet was visually quite bland. In contrast Neptune exhibited notable weather phenomena during the 1989 Voyager 2 fly-by.  The Great Dark Spot (top), Scooter (middle white cloud),  and the Small Dark Spot (bottom), with contrast exaggerated. Neptune's weather is characterized by extremely dynamic storm systems, with winds reaching speeds of almost 600 m/s—nearly attaining supersonic flow.  More typically, by tracking the motion of persistent clouds, wind speeds have been shown to vary from 20 m/s in the easterly direction to 325 m/s westward.  At the cloud tops, the prevailing winds range in speed from 400 m/s along the equator to 250 m/s at the poles.  Most of the winds on Neptune move in a direction opposite the planet's rotation. 
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