Weather is biome specific.
(Rough idea is.)
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All biomes are setup with Temperature, Humidity, Altitude and Vegetation parameters which are used during biome selection and blending in the world builder. The world configs can then define how the biomes should vary across the world.
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We then save these static biome maps so that it can be used by the weather simulation. Below are the Altitude, Temperature, Humidity and Vegetation maps from one of the live worlds. This doesn’t change as the biomes are fixed. The world below is fairly noisy but world can have clear bands of the biomes as you might expect from a planet with polar and equator biome variations.
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A weather simulation is then run on the server so that everyone gets the same weather. If you look in the distance or through a portal within a world then the weather remains consistent. Dark clouds in the distance means rain in the distance, etc.
The simulation uses the biome maps so that the weather is consistent for the biome. If you think it rains often in your settlement then you unknowingly placed your beacon is a wet biome.
The simulation drives temperature, humidity, elemental and wind direction.
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The simulation ticks so that the weather moves around the world and is biome suitable. Quick sample:
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This is then simplified for rendering:
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The clouds are also driven by the simulation. These images are for cloud coverage, type of clouds, precipitation of the clouds, normal vs elemental clouds, occlusion (?) and snow cover.
The elemental clouds should be coloured and standout against the normal clouds, but this is currently being blown out by the strong coloured day/night colours. Elemental clouds are an indicator for elemental weather. (Which will drive gameplay in the future in the same way that the snowy areas spawned more oortmas creatures.)
The snow cover map determines which parts of the world should be snow covered.
When a snow meteorite lands a spot is placed into the snow cover map to turn make the environment snow covered.
And yes we have joked about the idea of using these cloud maps for rendering clouds and snow cover onto the planets seen in the sky. But decided against it as it would require quite a bit of bandwidth and mask the player builds.
I think the main reason the majority of players miss the weather + biome association is because they don’t recognise a “desert” when the sand isn’t yellow. The non-earthlike palettes aren’t recognisable as biomes. Hence Boundless is often criticised for having little variation between worlds. I’ve often put this down to limited exploration as there is clearly huge variation in biomes (IMO), but it’s definitely not helped by the foreign colour combinations.