Hi, generally most bullies are very sensitive or intolerant to severe temperatures hot or cold, but having said that every bully is different in what and how much exercise they can tolerate and how much stamina they have. I have two EB's, one male and one female, my male does not do well in the heat or the extreme cold temperatures, and he doesn't like to walk very much. He mostly likes to go for his potty breaks and then runs back towards the house. When we try and go for longer walks with him, meaning a 15 min walk, he will flop or lay down, put all 4 legs to the sides and will literally refuse to walk any further. My female is the opposite, she loves to walk and loves to go on long walks, she would walk for an hour if we let her, but we don't. Bullies definetely don't do well when it is hot or humid, and they shouldn't go on long walks during the day when the sun is at it's hottest. They should be walked early in the mornings and in the evenings when it is cooler, and only for about 15 mins. During the day when its hot, they should only go out for a potty break, and then right back inside to the air conditioning. Also a bully should never be left outside unattended on a warm day, and not for long periods even when you are with them. They can become overheated very quickly.
In the winter when it is cold outside, the same rules should be followed. Although they won't overheat in the cold, they can get hyperthermia, and the extreme cold of the snow can cause pain to their paws, and even frostbite. It's best to take them on more frequent walks for shorter durations. Golden Retreivers are a bigger dog, with a thicker coat, and they are breed for being outside, they can tolerate being out in the cold, and they can exercise for long periods of time, they actually thrive on running and playing hard. Bullies aren't built for this, and because of their breathing problems, they don't do well with extreme temperatures, long walks, or playing hard for too long.