In which layer of the Earth's atmosphere do most weather events occur?

Most weather events occur in the troposphere, which is the lowest layer of the Earth's atmosphere. This layer extends from the Earth's surface up to about 8 to 15 kilometers (5 to 9 miles) high, varying with location and temperature. In the troposphere, the temperature generally decreases with altitude, leading to the formation of clouds, precipitation, and a variety of weather phenomena, such as storms, winds, and temperature fluctuations.

The presence of water vapor in the troposphere is a key factor that contributes to weather changes. Because this layer contains approximately 75% of the atmosphere's mass, it is also where most of the atmosphere's water vapor resides, allowing for the development of weather systems. Additionally, the mixing of air layers in the troposphere helps regulate different weather patterns, making it the most dynamic and varied layer when it comes to atmospheric conditions.

The other layers of the atmosphere—stratosphere, mesosphere, and thermosphere—play different roles in atmospheric processes but are not where weather phenomena primarily occur. For instance, the stratosphere is known for containing the ozone layer which absorbs and scatters ultraviolet solar radiation but features minimal weather activity.