Get the details behind our redesign
The state of the atmosphere at a particular time and place. Weather is described in terms of variable conditions such as temperature, humidity, wind velocity, precipitation, and barometric pressure. Weather on Earth occurs primarily in the troposphere, or lower atmosphere, and is driven by energy from the Sun and the rotation of the Earth. The average weather conditions of a region over time are used to define a region's climate.
Any of the chemical or mechanical processes by which rocks exposed to the weather undergo chemical decomposition and physical disintegration. Although weathering usually occurs at the Earth's surface, it can also occur at significant depths, for example through the percolation of groundwater through fractures in bedrock. It usually results in changes in the color, texture, composition, or hardness of the affected rocks.