Sky

Pick Sky in the tool column and its settings open in the panel on the right. Time of day is the control you will reach for most. It moves the sun, and everything in the world relights with it as you drag.

The panel also shows a Date readout and carries Latitude and Longitude. Those matter because they decide where the sun actually sits: the same time of day looks different at different latitudes, and that is what makes a world read as somewhere rather than nowhere in particular.

Day length sets how long a full day takes. Time runs decides whether the clock advances when you play.

While you build, the clock stands still, so the light holds while you work by it. Turn Time runs off and the game holds the hour you set. Turn it on and your game gets a day-night cycle that starts from that hour.

Two sliders cover the air itself: Cloudiness and Haze.

Haze is worth knowing about even when you are not thinking about weather. If a world looks washed out and you cannot see distant terrain, haze is usually the reason, and turning it down is the fix.

While you build, the haze is off so you can see the whole world. It comes back while Sky is in your hand, so you see the air your player will see while you set it.