I want to preface this review with the following observation: I love my sci-fi, but this has a very tenuous connection to the idea of a summer night at best, since in the plot you've shared in the submission page, these are conditions that would happen on this planet at pretty much any time of the year, just following the tides (if the tides followed seasons, that much wasn't made clear).
With that out of the way, let's begin.
First Waves. The track is actually quite lush and suggesting a forest or sea -- sounds of birds, water, leaves, lots of nice spicc strings, glittering high piano. Piano could use more dynamics, strings could use more volume automation, but that's not to say there isn't already. The writing here is really, really nice. It also conveys the idea that this is a habitable zone (which 300 Kelvin is, like 26 point something Celsius). The spiccato suggests that things are bursting with life. It could use a much louder section before toning back down, and looping again (like would happen with certain exploration themes in the likes of Ni no Kuni, for example).
Night Belt. The piano already suggests that it's calmer, less active, giving the impression of night-time. Any dynamics here are subtle. It could use more, to be honest -- not too much -- strings can swell, piccolos can trill in certain more exhilarating sections, all while the piano keeps that nice movement all the way throughout. How vast is this belt? Or, how wonderful? Are there island formations, beautiful stars to look at, creatures flying overhead? These are things that can, and should be communicated in your theme. It's calm and beautiful, but I also want my night-times on this theoretical ship to be filled with wonder as I'm out there under (presumably) a starry sky for however many hours, with the flames of the sun bearing down on one edge of the sky.
Some food for thought, I guess.
Otherwise, you've shown good writing and it was a pleasant listen. Well done, and all the best this jam!