I take lessons at a nearby stable but not in the summer. In SA, temps have been in the 100's. I ride with my 3 children and we will resume in a couple of weeks. I love it.
Riding as a thin trim woman is a lot more fun and one more reason to get the weight of sooner rather than later. I felt bad for the horses back, my bum, joints, heart, etc... Being fat is hard in so many ways.