Are clouds darker when the sun is out?

It's getting late in the summer and the rains are slowly, but surely, coming back to Vancouver. So when it's sunny here now, there are often big dark clouds in the sky as well. It may just be a trick of the light, or an emotional reaction, but are these clouds darker than the average clouds we get in the winter?

Sometimes when you can see the clouds in the distance between buildings they are very dark and have little white clouds in front of them. If you didn't know better, you'd think the mountains were getting closer. Of course, if the mountains were sneaking up on you your other senses, beyond just vision, would be screaming out warning signs and shaking your very existence into a new view of the world. It's very unlikely that the mountains are stalking you.

If every cloud has a silver lining... the silver needs polishing, dear. These clouds are dark and angry.

But when the sun goes behind one of the clouds, the clouds don't seem as dark. Is this just nature's way of showing you that the upcoming months of clouds and rain are not nearly as scary as they could be if the sun was always coming out? Are we supposed to be happy about the days of flood-fill gray with no detail in the sky?

I think the clouds are darker when it's sunny. I also think I think way too much about the rain that is coming. Could it be that after 10 years of living in Vancouver the rain is getting to me? Hmm, I guess that's better than having mountains sneaking up on you when you don't expect it, she writes, looking over her shoulder.