Oh my, you struck my heart with this piece! Yours and Sincuna's both about this precious companion. He talked about the rainbow bridge too in his reply.
Never underestimate the love of a dog and the owner. It's an unbreakable bond. I love hearing stories about dogs reuniting with their owners or saving the owners in a big way because they recognize danger.
My favorite stanza was the third because it was simple and had a good flow. I liked the idea of a tail not just wagging, but having its own wag; dogs truly have their own unique character. The title actually drew me in at first because of that abstract idea, but it's interesting to think about. You could mean wind as in literally, or what I thought about was that it was time, or reality, that catches up with us. We all at some point age, have to face death, suffering. It's a cycle. You may find another sun, or always have that light (that memory) to keep you warm. Comforting to think about.
Anyways, this was such a sweet, touching poem. Stay strong.