Ours all get a little jumpy on windy days but as far as sunny or not sunny maybe he has SADD I notice ours get happy on those days that are bad for flys, too windy, too cool. They get reallyhappy right after the first frost.
But I mean this is a constant thing. Wednesday was a beautiful day and Sonny behaved perfectly!!
Thursday was overcast and rainy...and he was a total brat and wouldn't listen at all
Friday was a beautiful day and he listened perfectly.
I'm thinking it's just something that I can't really change. I've tried just working him on bad weather days...but it's hard because he won't listen to my cues, won't collect, won't really do anything (he slammed on the breaks when I asked him to tror over groundpoles...he acted as if I asked him to take a 6 foot jump!)
Any ways I can work that out of him? Or should I just live with it? If he is bad I always end him on a good note, whether it's leg-yielding good, or doing a circle fairly good...but it's hard to end on a good spot....on Thursday I thought I'd never be able to end on a good spot!!
Next rainy/cloudy day I'll just probably do some groundwork with him and start from there and hopefully that will work!
Is it always windy when he acts up? Some horses get naughty in the wind because of all the smells being blown at them. That's just something that time will take care of...although I recommend getting one of those special tying things where you loop a long rope on what looks like a half of a snaffle bit (I'm sorry, I don't know what they're called! Real helpful, huh?). They give very slowly when the horse pulls back, reducing panic at being restrained. You might just try leaving him tied to it all day on a cloudy/windy day until he realizes there's nothing to be afraid of...he might just've had a bad experience.
Heck, maybe he's like me and gets headaches when the barametric pressure rises (I can usually predict rain, LOL) Or his joints get achy, or just plain old sleepy on rainy days. I am usually lazier on cloudy days than sunny ones. I don't know.