Marty runs up the steps from the underground mall, looks at the activity back across the square, and hears a beeping noise.  He realizes it’s coming from his jacket and notices a blinking light at the bottom.  Pressing it, he unknowingly engages a drying mode.  “Drying mode: on.  Jacket drying. Your jacket is now dry.”

Somewhere in Marty’s jacket is a sensor that recognizes that it is wet.  Pressing the button activates rather powerful fans that are able to blow air to dry the inside of the jacket (and Marty’s shirt hair).  Presumably, the jacket’s drying mode would be intended for drying out the jacket and clothing after a rainstorm.  It seems rather unlikely that enough people would end up swimming in jackets for that to be the only reason for a drying mode.  The sensor that caused the beeping to start must either be on a delay timer (because it didn’t start beeping until after Marty came up the steps from the mall) or must sense that it has stopped raining (or being submerged) and that it’s okay to start drying.

We don’t know if the jacket had other tech built into it.  Given the drying mode, heating and air conditioning modes wouldn’t seem like a stretch.

Conceivably, someone could make a self-drying jacket by putting some fans and tubing into a jacket, but that would make the jacket rather heavy and uncomfortable.  Currently, nothing like this exists in our 2015.

Prediction Accuracy: Failed