Physically the horse is a thing of incredible beauty and unbelievable wonder. There are very few things in the world more beautiful then a well groomed horse in motion. It doesn't matter if that horse is performing a complicated dressage test, running down the backstretch, sailing over a jump, or chasing after a calf, the horse is a thing of incredible beauty.
In addition to being structurally designed to steal your breath , horses have a hair coat that is designed to withstand the elements. As long as they have plenty of fresh water, lots of roughage and a good shelter there is very little reason to blanket a horse. Most breeds have skins that are fairly tough. In addition to a tough skin they are blessed with a wonderful hair coat. Their hair is designed to fluff and catch pockets of air, once the air is caught in the hair it is warmed with the horses body heat. A healthy horse with a good hair coat will stay warm, wrapped in their air pocket throughout the winter. If you don't believe drive past a field of unlamented horses in the winter, chances are pretty good that they will be completely ignoring any shelter they have been given. The only time the average horse has a real problem with staying warm is if they have gotten wet, or if their hair has been flattened by mud.
Just because the average horse doesn't need a blanket in the winter doesn't mean that they all don't. Several breeds, including Arabians and Thoroughbreds, have thin skin that is easily chilled. Older horses can also have a difficult time staying warm.
Horses that have had an injury or illness that caused them to loose hair. Horses that are underweight are another group of horses that should be watched carefully to make sure they don't develop a chill.
There are a variety of reason's horse owners might choose to leave their horse blanketed during the winter months. Some people who ride during the winter months choose to save time cooling out and waiting for their horse to dry after it has been worked by body clipping, horses that have been body clipped must be blanketed.
Several show barns might decided to leave their horses blanketed so they are able to attend shows in the early spring with a horse that is sleek and shiny as opposed to a horse that is covered in a thick winter fuzz.
In the summer there are three main reasons a horse owner might choose to blanket their horse. Some horses, especially light colour ones are prone to sunburn, wearing a light weight blanket allows these horses to be outside without burning. Some horses are highly susceptible to bug bites a turnout fly sheet prevents bugs from biting their sensitive skin. Horse owners who spend a great deal of time on the show circuit will use a light weigh sheet to prevent the sun from bleaching their show horses coat. A few horse owners will even resort to a heavy weight turnout rug in an attempt to help sweat off a few of their equine friends excessive pounds.
