My dog measures about 63cm along the back. I got the size 65 and it's quite big on him, his chest measures 73cm. It's large, so if you're unsure, the sizes are generous. I should have chosen a size smaller.
Basically, this raincoat is really nice and lightweight, and it fits my little Urmel perfectly. However, the opening for attaching the lead to the back – which is actually mentioned in the product description – is missing. The opening is at the collar, so you can only attach the lead to a collar, not to a harness. That's why I'm taking off one star.
After about 2 days, some threads started coming loose (seam coming apart). The leg elastics are very thin and large. However, the neon colour is nicely reflective. Under the jacket, the fur stays dry.
It would be nice if there was more belly protection for female dogs.