While the process is directed by the change in daylight, external temperatures will also play somewhat of a role, in that a horse that is blanketed early will not develop as thick a coat.

If you do blanket, remember that a horse’s fur fluffs out when it’s cold. This adds air space, like your down jacket has, and that air fills with warmth making the fur more efficient. Blankets crush down that air space, so you need a heavy enough blanket to provide true warmth. A thin sheet may protect a horse from rain, but it may not provide much warmth and may leave the horse colder than if he had no blanket.

According to some studies, the tissue under the wrap, along with tendons, can potentially overheat in hot weather.