Yes, they grow here. Need heat to ripen fruit (ie: last two Summers) - also need two varieties for pollenization. I have eaten Washington Grown PawPaws the past five years --- I know several people that grow them - I do not have room to grow them myself (yet!) Raintree nursery carries them.

The national repository for Paw Paws is in Corvallis, Oregon. I know it's a bit south but it is encouraging. Their collection of mature trees is very impressive and are fruiting prolifically. I live in southern Oregon and have 5 mature trees (about 8-10 foot tall) No fruit set this year, last year had a couple. Hoping for greatness next year!!
Good Luck
GP