No. Was riding my 5 year old this evening while it was thundering and she didn't bat an eye lid. Can rider her when its blowing a gale and she is fine, I've had lessons where I can't hear a word the isntructor is saying and the horse is being blown sideways, and she's 17hh and she's still fine!!
She lives at the top of a big hill just outside Newcastle so she is more than used to wind and horrid weather!!
My horse gets SAD (Seasonal Affective Disorder) I am sure of it!
She is just a much much nicer person when it is sunny. Her actual temperament changes and will snuggle with you and let you kiss her nose rather that trying to take your arm off at the elbow