Since horses would not go out voluntarily at midday in very hot weather, do not put your horse out to pasture in the blazing sun at midday, but rather postpone grazing until cooler times of the day. If your horse is out in the pasture all day, make sure that there is enough shade and water for all the animals, not just the most senior. Horses should also have free access to a salt lick to prevent nutrient deficiencies caused by sweating. You can also feed your horse electrolytes to compensate for very heavy sweating, especially in the height of summer.
Many horses have problems with their circulation, especially when temperatures fluctuate and during the first really hot day of the year. In this case, you should not work your horse on such a day. However, a little exercise is necessary and also prevents colic. The first hot summer day of the year is a good opportunity, for example, to wash your horse's tail and then take it for a long walk. It is best to put a fly rug on your horse, as midges and horseflies are particularly aggressive on hot days. If your horse is fit enough to ride, do not overtax it and pay close attention to its signals. Allow your horse a comfortable walk in the shade after light work.
Most horses love to be showered with water after riding in summer. Be careful never to spray your horse with cold water when it is very hot, as the horse's circulation could suffer. Let your horse cool down first and do not use ice-cold water. Start very slowly on the legs until the horse has become accustomed to the temperature and only then slowly spray the neck, chest and saddle area.
Use a sweat scraper to remove the water from the horse's coat and leave it to dry in the shade for a few minutes. If necessary, you can put on a fly rug to allow your horse to cool down.
You should also take extra care of yourself on hot days, always drink enough and use sunscreen if necessary. Riding helmets that allow good ventilation are also a boon at the height of summer. Light summer riding gloves and breeches for summer, as well as technical riding tops, also help to prevent heat build-up and to transport moisture easily to the outside.