I've tried to be careful about the pawpaw varieties that I planted.  I researched online to see which ones bear earlier.  However, there is not a lot online about when each variety bears, especially in the Maritime Pacific Northwest.  Our cool summer climate might make them later.  If it looks like oncoming frost, and there are pawpaws still on the trees, will they be wasted?  Can they be ripened off the tree?

I tried picking two pawpaws two weeks ago, and placing them into a dish with a banana, covering with plastic wrap.  As it happened, pawpaws started falling off the tree, ripe, this week.

This is not a controlled research experiment.  I did not test to see if the ripening was the same without the banana, or test multiple varieties.  It's more, this works for persimmons, so maybe it might work with pawpaws.

As it turned out, the tree-ripened pawpaw was more mushy.  I think it was a little sweeter and had a little richer, more tropical flavor.  The banana - ripened pawpaw was easier to separate the seeds and more of an avocado consistency, also very tasty and sweet. 

My conclusion is that if frost is coming, and I have a bunch of unripe pawpaws, I will consider ripening pawpaws indoors, at least some some with the banana or apple in a sealed container.  I can't say it's necessary or helpful, yet, but it at least did not seem to do any harm.