Would it be possible to have multiple skyboxes? It would look amazing if we could fade between skyboxes with the day cycles.
For example you could have two skyboxes: one day skybox with clouds and blue sky and another with just stars. You could make the day cycle fade the skybox to the night one as the sun goes below the horizon. I would say that the ideal amount of skyboxes would be 4. Sunrise, day, sunset, and night. You could do it with just three but we can't rotate the skybox.
The fading would probably change the alpha of the first skybox while the second one is fully opaque but somehow behind the first one.