Temperature Inversion

My field recording work is often exterior, so I am often dependent on the weather…
Wind & rain ruin recordings (unless that’s what I’m recording) but checking the hourly weather forecast I keep noticing how the wind always dies down at night… Why is that?

Answer: temperature inversion
Longer answer is here

“The wind speed tends to decrease after sunset because at night the surface of the Earth cools much more rapidly than does the air above the surface. As a result of this difference in cooling ability, it doesn’t take long for the ground to become colder than the air above it. The air in close contact with the ground — say in the lowest 300 feet of the atmosphere — then becomes colder than the air above it.

This circumstance leads to the development of what is known as a temperature inversion. Inversions dramatically reduce the amount of mixing that occurs between different vertical layers of the atmosphere. As a consequence, once the inversion sets up (after sunset), it is much harder for fast-moving air above the ground to mix down to the surface, where it could appear as a gust of wind. During the day it is very easy for the air to mix and cause surface gusts.”