what layer of the atmosphere does weather form in and why?

Answer 1

The troposphere is the layer in which weather occurs. Above the troposphere is the stratosphere, which contains most of the ozone that blocks most UV light. This layer has very little to no vertical mixing of air and is warmer than in the troposphere (due to energy released from the ozone reactions here), the warm air from the troposphere cannot rise past this layer and thus weather cannot go into the stratosphere. Therefore, the weather is trapped in the troposphere. It is caused by the heating of the Earth's surface by the Sun's infrared energy. This heated air rises (because it is less dense than the cooler air in the atmosphere, which does not get heated as much as the surface). If the rising air which absorbs the energy from the surface via conduction has a certain amount of water vapor in it and does not form a cloud, it has a low relative humidity. When the air rises to a specific height, the relative humidity increases and the air becomes saturated. This creates clouds.

Answer 2

The troposphere. This is the layer closest to the earth and is easily affected by solar heating. Uneven heating of the earth surface by the sun causes the weather.