A horse blanket includes a blanket shell to protect a horse from cold and moisture, and when needed in colder weather, it can be augmented by insertion of one of several insulators into a space provided between layers of the blanket shell. The blanket shell's outer layer is waterproof and weather-resistant, with the inner layer that bears against the horse having a surface comfortable to the horse. The outer layer has one and preferably two elongated access openings, positioned to be at left and right sides of the horse, for inserting, removing or exchanging insulative inserts.
