Painting the effects of weather on outdoor environments is something I've become specifically interested in after years of painting generic 'nice day' lighting setups.

Rain: wet surfaces behave like imperfect mirrors. Pavement reflects sky and buildings with slight distortion. The reflectivity is higher on flat horizontal surfaces than on vertical ones. Rain itself is mostly invisible unless backlit — you see the effect on surfaces more than the rain directly.

Stormy light: dramatic and directional. Clouds create dark areas with shafts of light breaking through. The contrast between illuminated clouds and dark sky or dark terrain against a light sky break is extreme. This contrast creates the drama.

Overcast after rain: the light is soft and the wet surfaces add specular highlights to otherwise matte materials. This combination — soft ambient light plus selective specular — is one of the more beautiful and underused lighting setups in environment painting.