When I rode in Manitoba the horses were never clipped. Our riding had to be adjusted to not get them sweaty. Even the show horses weren't clipped. They were mainly ridden at the walk with a little trotting and always on the trails. We did have to towel them off as the barn was only about 10* warmer than outside.
This is Ro's clip last winter - I really like the idea of this type of clip - note that the belly isn't shaved. I've always done a full body (leaving half the head, legs, and a patch for the saddle) but I think I will use this one instead, it looks much kinder to a horse that is turned out most of the time.