Why do commercial airliners encounter very little turbulence above 25,000 feet?

Question

Water vapor has mostly disappeared at colder elevations and its effect on weather turbulence.

The jet stream produces a much smoother flow of air.

There are no clouds above 25,000 feet.

The air is so thin at altitudes above 25,000 feet that turbulence has much less effect.

Answer 1

The most accurate explanation for why commercial airliners encounter very little turbulence above 25,000 feet is primarily due to the influence of the jet stream, which can provide a smoother flow of air.

At higher altitudes, the atmosphere tends to be more stable, and many types of turbulence, such as convection turbulence associated with weather systems, diminish. While it’s true that the presence of water vapor decreases at higher altitudes (which can affect weather turbulence), it’s the organized flow patterns found in the jet stream and the relative stability of the air that contribute to the smoother flying conditions commonly experienced above 25,000 feet.

It's also worth noting that while there can still be turbulence at these altitudes, it tends to be less frequent and less severe compared to lower altitudes, especially in the case of clear air turbulence, which often occurs above the jet stream at even higher altitudes.

So, the best answer relates to the smoother flow of air associated with the jet stream at these higher altitudes.