Mountain breeze and valley breeze
A mountain breeze and a valley breeze are two related, localized winds
WINDS , is a Japanese communication satellite. Launch was originally scheduled for 2007. The launch date was eventually set for 15 February 2008, however a problem detected in a second stage manoeuvring thruster delayed it to 23 February...

 that occur one after the other on a daily cycle. They are not the same as katabatic wind
Katabatic wind
A katabatic wind, from the Greek word katabatikos meaning "going downhill", is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds...

s, which usually occur on a larger scale.

Mountain and valley breezes form through a process similar to sea and land breezes
Sea breeze
A sea-breeze is a wind from the sea that develops over land near coasts. It is formed by increasing temperature differences between the land and water; these create a pressure minimum over the land due to its relative warmth, and forces higher pressure, cooler air from the sea to move inland...

. During the day, the sun heats up valley air rapidly. This causes it to rise, causing a warm, upslope wind. At night, the process is reversed. Mountain air cools rapidly at night and "falls" downslope, causing a wind going in the other direction.
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