How would I implement a real-time weather
system in panda 3d? I would like to do rain, clouds, and maybe even wind.
rain can be done with simple particles, or big cylinders with moving rain-textures which follow the camera (i’m sure there are more options but those are easy and common). rain and fog make a good combination.
for clouds have a look at
http://www.vterrain.org/Atmosphere/Clouds/
vterrain is an excelent resource for other stuff too.
about wind… i guess you are talking about simulating plants moving due to wind. if so. you can either use the common ways to animate geometry (vertex/bone based animation). or you write a small vertex shader which does the job for you.
have you looked at the nature-demo on the forum? if not. search for it 
at least it has some gras and sky. not game-industry-standart but still good and might give you some hints
How does vertex animation work in panda 3d?
Can I use blender to do it?
developer.download.nvidia.com/bo … _ch07.html
This looks like a feasible way to do grass in the wind.
hm… the setShear() stuff could be intresting,thought.
btw. afaik chicken doesnt support export of vertex-based animatinos yet. so far it was simply not possible to read out the data via blenders python api. might have changed so it might be possible to code. dunno exactly.
The nature demo includes wind applied to the grass iirc. Not on a vertex basis but on texture coordiantes. (check yourself, i think it was moving)
Does anyone have a good texture to use for this tutorial?