What weather phenomena are not related to atmospheric humidity?

A, fog is a small water droplet formed by evaporation and condensation of water, which is a liquefaction phenomenon and related to atmospheric humidity, so A does not meet the meaning of the question;

B, the wind is formed by airflow, which has nothing to do with atmospheric humidity, so B meets the meaning of the question;

C, snow is formed by condensation of water vapor in the air, which is related to atmospheric humidity, so C does not meet the meaning of the question;

D, frost is formed by condensation of water vapor in the air, which is related to atmospheric humidity, so D does not meet the meaning of the question.

So choose B.