Is condensation in an airplane normal?

Episode 1495 (1:17:17)

Mike from Maine
Johnny Jet on a plane

Mike is a commercial pilot and he called in to talk about Johnny Jet's tweet about mist in the airplane cabin. Mike says that airplane mist happens a lot in humid climates when the cold air from the airplane's AC meets the warm air of the cabin. It's very normal, and only happens when the plane is at the gate and hooked up to an air conditioner to keep boarding passengers cool.