# Does warm air on a macroscopic scale tend to produce more wind (turbulence)?

I am a private pilot and noticed something. Flying in the colder winter days seems way calmer and less turbulent to me than flying during the summer. Now because I do not have that much of experience this might just be coincidental. And of course I know that on any day there are so many factors that weigh in when it comes to the weather. Still, my question is:

Is there a physically explainable tendency for warm days to have more turbulent air / a higher wind?

A thought that might support my experience:
Because of the ideal gas equation
pV = nRT
I see that a higher temperature results in a greater pressure gradient , thus leading to more wind. Problem I see with this explanation is that this might explain air flow/wind on a large regional scale, not the turbulence I experience with a small GA aircraft.

Furthermore I thought that because of higher temperature, the air molecules have more kinetic energy and fluctuate more. Although this might be true, I realized that this is just an explanation of the microscopic scale and should not be of any significance answering the question.

• Vertical air movements are caused by the sun heating up the surface which heats the air. This is used in hang gliding. But for better answers you could try earthscience.stackexchange.com
– user137289
Commented Oct 13, 2020 at 19:18

In summer, the sun is more directly overhead and more intensely heats the ground surface up. The heated air right next to the surface is more buoyant than the slightly cooler air above it, which is a dynamically unstable condition. The hotter air protrudes up into the cooler air and rises upwards, drawing in more hotter air from around its point of origin next to the ground. This creates a column of rising air with a significant vertical velocity, and each time you fly through one of these, you get a kick in the pants and when you exit that updraft, the bottom falls out of your stomach.

In winter, the sun is at a slant to the ground and the ground is subject to less intense heating and the tendency to form those thermal updrafts is less.

You will find that in the summer, you will have smoother air for flying in the early morning because overnight, the hot ground cools off and the thermally-driven motion of air dissipates.

• Nice, how could I have not thought about that? So you would come to the conclusion that indeed, flying in cooler air tends to be calmer? Commented Oct 13, 2020 at 19:24
• In general, yes. In the western US where I live, the smart student pilots book their lessons for right after the FBO office opens in the morning! Commented Oct 13, 2020 at 19:28