Commander 114, S/N 14358

I have noticed lately, that mist is building up on the inner side of the outer window in the left side door during climbout. Obviously due to of saturation of humidity in the inclosed air. Sometimes, I have to look out of the little triangular window to locate other traffic etc. However, after a while it clears up again. It is only on the left side, and it hasn't been there before. Window in the right door is no problem.

What is the most likely reason to the problem and what can I do to solve it?

Lookimg forward to good answers.

Regards Finn(air).