coat change after groom?

I searched (on my phone... But I still searched) and didn't find any old topics on this, but sorry if it had already been covered a time before and I missed it.

Tate's coat has changed since his last hair cut. I mean mainly texture-wise. It has changed in color, but we have also been outside quite a bit, and the reds in his hair have really come out this summer (they didn't last summer, so we currently have a little red-head). His hair is much more coarse than it used to be, and doesn't seem to be growing back as curly. Any idea what would cause this? Could it possibly be because it has been exposed to the sun more than it was in the winter?

I noticed this today when I was rubbing on his flea spray (don't worry, its holistic) and he wasn't the soft, downy baby he once was.

He isn't a puppy by any means (well, unless whomever had him before quickly ruined his teeth).