I'm having the opposite problem. Both of mine are refusing to go out in the sun at all. They both sit in the back porch until I relent and let them back into the house. They're not usually bothered by the sun, in fact one used to enjoy soaking up the sunshine. I am baffled by the sudden change. Maybe they are just getting old.
My mum lives in the desert and has a husky (I know ). The dog loves sunbathing in 40 degree + weather. My mum speculates that actually her fur keeps her insulated and cool, as well as warm. Or else the dog is just crazy.
We got a rescue terrier at Christmas. She has overcome all sorts f f obsessions, but now has turned her attention to flies and bees. She is leaping up every few minutes trying to eat them. If they settle on the ceiling she yelps at them