I've been preparing for my move to Portland for almost a year now. Most of my stuff has either been given away, donated or packed up.
To get ready I made my dog, Sweetsie, a harness so she can sit in her carseat during our trip across country. Then I made her a raincoat for Portland's rains.
She doesn't have the proportions for ready made dog clothes. I could never find a harness to fit her. The smalls are too small around her chest. The mediums are way too large. So I used her long and thin measurements to make her one.
I tried a doggy raincoat from Amazon. It fit her but she wouldn't move. The hood smooshed down her ears. So I made her one from what fabrics I had on hand (not packed yet). I used turquoise oilcloth from Mexico lined with fleece for the body of the coat. The coat is made from one of those heavy plastic bags that pillowcases or napkins are sold in.
The secret to making a doggy raincoat is to make the hood detachable. It's easier to construct and fits over the ears better.
Sweetsie will wear it but she's not too happy about it. But she hates the rain so I think she will learn to appreciate it.