…interior state? It’s totally slipping my mind and google is useless.
Like if the character is experiencing inner turmoil, then it’s dark and storming.
Anthropomorphism is the general term for imputing human characteristics on animals or inanimate objects, but I’d swear there’s a more specific term for what you’re talking about.
I usually call it “heavy-handed”. 
I suspect the term for the technique you’re looking for is “the pathetic fallacy” (Wiki) or “the anthropomorphic fallacy”.
I always thought it was “foreshadowing” but that applies to more than just weather.
Pathetic Fallacy was the answer - thanks!