Not much, be careful cuz our bullies can easily overheat. Down here in southeast Texas it's very hot, very humid and Holly loves to sunbathe! We always keep a sharp eye on her and give her ice cubes, make her come back inside to cool off and drink some water. I will take her on a walk early in the morning when it's much cooler but we don't walk in the evening because it's too hot. Be careful and always monitor your bully when it's outside in the summer heat.