The builder
Weather
Weather adds rain or snow over time. The panel appears only in worlds that have a weather system, and most of what it shows comes from that system rather than from us.
It is a panel only
Weather has no verbs on the bar and nothing to drag. Everything happens in the panel.
If your world has no weather system, the panel is empty. That is the tool being honest rather than offering settings that would write to nothing.
Intensity and snow cover
Two controls are always named the same way: Intensity, which is how hard the weather is coming down, and Snow cover, which is how much snow has settled on the ground.
Snow cover is separate from falling snow on purpose. A world can be under deep snow on a clear day, and it can be snowing onto bare ground.
Everything else comes from your world
The rest of the panel, including everything under Advanced, is generated from what the weather system in your project actually exposes, under the names that system uses.
This means two projects can show different weather controls, and that is expected. The panel reflects the real thing rather than a list that would go stale.