Ponchos and Serapes
For night riding and for all day riding when the weather is quickly changing I find no garment to be better suited than a poncho or, for very cold weather, a serape.
Ponchos of heavy horse blanket material shed briers and brambles quite well. As soon as we reach a clearing the poncho flips back over the shoulder to allow for riding in comfort in warmer weather. It works especially well for night riding in the woods for the same reason.
Horses need to be desensitized to the garments flapping in the wind before their use. A long serape flapping wildly in the wind can spook horses who have not been trained to them.
Completely aside from their wonderful function, riding in a poncho keeps one from taking the dangerous step of looking like everyone else. Looking like everyone else, as Mao-tse-Tung understood, leads to thinking like everyone else.
Thinking like everyone else leads to not thinking at all.