How do I build an exchange library that will last in PNW weather?

Here is one site you can look at that may help you. In researching your question it seems that in some cases even doing this is a violation of city, county, state codes, so you'd want to check that out first.

Here's one link about people who did it.

http://archive.jsonline.com/features/home/10-things-to-know-before-building-your-little-free-library-b99310728z1-268522622.html

Then this frequently asked questions about little lending libraries such as you are wanting to create:

https://littlefreelibrary.org/faqs/

I hope this info is helpful to you.........

many smaller towns don’t have a library, there is a book shed in one town...books are donated, give one take one. At one time there were more than 200 paperbacks on my shelves. When I found a digital version, the paper version went there. The building was litterly a wooden shed...riding lawn mower size. Shelves installed for books.

The really cool thing...one of my books I had donated found its way over sea. it was a more popular book at one time, aNd I purchased it. I had put my email adress in the book so the person I loaned it to could let me know when they were returning it. They never did, and I got a replacement. Last year I get an email...wanting know if I was a real person And do I want my book back? it was a service person across the pond. I told them to pass it around.

okay this is getting a bit weird...my aunt and cousin just called...they are planning a trip to an Amish run grocery store..do I want to go with ..do we need to stop at the book shed?..

Contact the nearest library and see if they have a program already going and find out if it can be extended to your town. They may already have the supplies for the exchange books.

I think you are talking about one of those small "libraries" that people have in their front yards, aren't you? We live in Maine and it gets pretty cold and snowy here and they are abundant in my town. I don't know how cold it gets in Washington state but we can go down to zero or below. And although we have a new beautiful library in our town, we also have a facility called a 'swap shop" and we get lots of books from there. You don't have to leave any. You just take as many as you like. (also as much of anything else you see there that you like)

insulated book shelves or cupboard or Shed with a stool...............

Thank you all! I will do more research before I actually install it