I dont feel as if you have an issue with anything else, what you are seeing is a screenshot taken around the same time of day as the last one with the sun in the same position......to be more precise up high and off to the left of that image.... This setting you have will absorb more light then reflect it, similar to real life, here is a real image with the sun behind a cloud: http://upload.wikimedia.org/wikipedia/commons/8/81/Cloud_in_the_sunlight.jpg The clouds are a simulation on to themselves and are dynamic in the very fact that they change under a variety of conditions..... Take a look at the gallery, some look like the image above and some have more depth it all depends on a bunch of variables: http://skymaxx-extreme.com/?page_id=2 But to sum it up belimi, maybe you are seeing more then me, I would try and remove the HDR environment add-ons........