The sun was glowing a dull red overhead. This was part of the reason he hated Tuesdays. The sun they got on Tuesdays and Thursdays wasn’t good for anything. He much preferred the sun they got Mondays and Wednesdays, which was bright and yellow, and much the way he thought suns should be. Of course, some people like the blue-tinged sun that rose on Fridays and Saturdays. It could be worse, he thought. It could be Sunday. Those were always dark. Luckily, the Law had killed Sunday, so he didn’t have to put up with that anymore.
This paragraph was where I upvoted. This is fascinating, unique worldbuilding. Worldbuilding usually does not serve as a hook, more a promise ('you will get to see dragons in this story', etc), but here it does. (And already before this, the awkward, unreliable mechanical horse and the whalecatching were entertaining enough to work as hooks themselves.)
The rest of the story is also excellent.