What is the name of the layer of the Earth's atmosphere where most weather changes occur?

The layer of the Earth's atmosphere where most weather changes occur is the troposphere. This is the lowest layer of the atmosphere, extending from the Earth's surface up to about 8-15 kilometers (5-9 miles) high, depending on geographic location and season. The troposphere contains the majority of the atmosphere's mass, including water vapor, which is crucial for cloud formation and precipitation. This layer is where atmospheric phenomena such as storms, rain, and wind patterns develop.

In contrast, the stratosphere, mesosphere, and exosphere do not typically experience the same weather changes as the troposphere. The stratosphere, for instance, is where the ozone layer exists and is characterized by a more stable atmosphere with little weather activity. The mesosphere above it is even more stable and cooler, while the exosphere is the outermost layer, where the atmosphere transitions into outer space and contains very sparse air. This lack of substantial air density in the upper layers means that they do not support the weather systems we experience at the Earth's surface. Therefore, the troposphere is uniquely essential for understanding weather.