Overnight tranquility

[brianposter]

Could someone explain what decides whether the wind will, or will not, decline overnight.

[brianposter]

Bump !

[Earthshine]

Normally the atmosphere is more unstable during the daytime especially during sunny days when convection occurs.  This results in winds as the atmosphere is heated from below.  During night the surface cools and the atmosphere becomes more stable, reducing winds.  Of course if there are features such as areas of low pressure these can override any local perturbations and result in winds during both night and day.