August 17, 2012, 10:04:30 am
Hi 123przemo, this is a known bug, i.e. that all Weather settings are reset to 0 the next time you load a given scene.
The problem is that we have been unable to reproduce this bug, since it happens so rarely; I have personally only ever experienced it once over the past 1 1/2 years. And we have about 10 user reports so far. If it happened more often, the developers would be in a better position to solve the problem.
In summary, all you can do is to load an earlier version of your scene, and then use the Weather settings in the old version to reconstruct them in the corrupted version of your scene.