Hot Weather Horse Care Essentials: Keeping Your Horse Healthy, Hydrated & Comfortable
Warm weather is one of the best parts of owning horses. Longer evenings, competitions, hacks through the countryside and more time spent outdoors all make summer enjoyable.
But hot weather also places extra demands on your horse's body. Increased sweating, changes in grazing, travelling, competitions and poor air quality can all affect hydration, digestion, respiratory health and performance.
The good news? A few simple management changes can make a huge difference.
When is it too hot to ride?
Travelling and competitions increase heat load, even before exercise begins. Standing on a lorry or trailer generates heat and many horses begin sweating long before they've entered the warm-up arena. If you need to travel, increase airflow by opening windows and vents in the horse area or consider the use of fans if it is safe and practical to do so. Make sure you pack plenty of water in case you are stopped for any period of time and need to cool the horses.
Temperature is only part of the picture when assessing the risk of heat stress. Humidity plays an equally important role and the combination of temperature and humidity is what is refered to as the Heat Index - how hot it "feels". Once air temperatures exceed around 32°C and relative humidity rises above 70%, the risk of heat stress increases significantly. Horses regulate their body temperature primarily through sweating, but when the air is already saturated with moisture, sweat cannot evaporate as efficiently. Because evaporation is what removes heat from the body, cooling becomes much less effective, making it harder for horses to dissipate heat during exercise.
Horses face a much steeper cooling challenge than we do. A large proportion of their body is active skeletal muscle and muscle contraction generates substantial heat as a by-product of movement. At the same time, a horse's body surface area is small relative to its overall mass - so there's proportionally less skin available to release that heat through sweating. Together, this means horses build up heat faster than humans do, but have less capacity to shed it, making them significantly more vulnerable to overheating during exercise or in warm conditions.
Heat Index for Horses:
The chart below provides a useful guide to assessing these conditions. Yellow indicates that exercise is generally considered safe for horses that are fit, healthy and acclimatised to warmer conditions. Red suggests extra caution is needed, with reduced workload, regular rest breaks and careful attention to hydration and cooling. Black represents conditions where the risk of heat stress is considered too high, and strenuous exercise or riding should be avoided altogether.
Adapted from published equine heat stress guidance including AAEP/US Equestrian and FEI recommendations.
NB this is a guide only - fitness, acclimatisation, wind, cloud cover, solar radiation , rider weight and workload all influence heat stress risk, so the chart above should be viewed as a guide rather than an absolute rule. Use your own judgment and assess your own horse’s fitness level when judging safety. If in doubt – don’t ride. Planning ahead helps reduce the risk of unnecessary stress for both humans and horses!
The hottest part of the day during a high heat index period is not the best time to exercise your horse and should be avoided wherever possible.
During hot weather ideally:
- Ride early in the morning or later in the evening.
- Work in shaded areas if possible
- Reduce work intensity on exceptionally hot or humid days.
- Allow longer warm-down periods.
- Give your horse opportunities to drink before and after exercise.
- Build additional recovery time into your routine.
How to get your horse to drink more
Water is the single most important nutrient your horse needs during hot weather and hydration starts long before your horse looks thirsty.
"Water accounts for approximately 60% of a horse's total blood volume, therefore losses through sweating can quickly cause significant dehydration if not addressed." explains Charlotte Radley, MRCVS. Every major system relies on adequate hydration. Water helps regulate body temperature, transport nutrients, support digestion and lubricate joints. As temperatures rise, a horse’s water requirements increase dramatically, "a horse can easily lose 12l of fluid per house of sweating during strenuous exercise."
Always ensure your horse has unrestricted access to clean, fresh water whether they're at home, travelling or competing. Dark coloured buckets or troughs attract the heat and can lead to higher water temperatures and faster algae formation, so consider offering alternative lighter coloured buckets and/or place buckets in shade if your main trough is dark. Regularly cleaning the water trough and topping up with fresh water throughout the day will help to keep the temperature down. Take care when filling troughs if you use a hose reel and it is left in direct sun. Water left in a reel exposed to intense sunlight can reach scalding temperatures, so run off any excess and check temperature before applying to your horse or adding to their bucket.
Offering a variety of water options can tempt your horse to drink more. You can add suitable horse herbs to make a water buffet (Gut Food is a great option for this with a unique herbal blend to tempt most fussy feeders!) or offer electrolytes for horses like UltraElectroS in a separate bucket, but never add electrolytes or herbs to their main or only water source.
If you are competing or training during hot weather, be aware that some horses naturally drink less away from home, so encouraging water intake becomes even more important. Practice getting your horse to drink from container water or find a flavour that they can’t resist to add to buckets to encourage drinking when out. Offering a sloppy mash of their favourite feed mixed with a large amount of water is another option for those that refuse to drink and feeding soaked hay can also help contribute to water intake.
Simple ways to increase your horse’s water intake include:
- Adding water to feeds
- Feeding soaked fibre where appropriate
- Taking familiar buckets when travelling
- Offering water regularly during long journeys
- Keeping troughs clean and cool
Why sweating causes your horse to lose electrolytes
Sweating is your horse's natural cooling mechanism, but it doesn’t just mean water loss. Every drop of sweat contains important minerals or electrolytes, including sodium, chloride, potassium, calcium and magnesium.
These minerals are essential for:
- Muscle contraction
- Nerve function
- Maintaining fluid balance
- Recovery after exercise
- Encouraging normal drinking behaviour
Simply replacing water isn't always enough after prolonged sweating. Whether your horse has been hacking, competing, travelling or simply standing in a hot field, electrolyte losses should be considered as part of their summer management. During hot weather and increased sweating electrolytes should be added to your horse’s feed to encourage drinking and ensure minerals lost in sweat are replaced.
What is the best way to cool a horse down?
Modern research has changed the advice around cooling horses. Continuous application of cool water is now recognised as one of the most effective ways to reduce body temperature.
Remove tack promptly, move your horse into shade where possible, encourage airflow and continue applying cool water until breathing and recovery begin returning towards normal. Resist the temptation to scrape the water off. As the water evaporates from the skin and coat, it absorbs heat energy, helping to cool the horse naturally - just as sweat cools us. Scraping away all the water removes much of this cooling effect. Instead, continuously apply cool water and leave a thin film on the horse to evaporate, particularly if there's a breeze or good airflow. If the water becomes warm, simply reapply fresh cool water to maximise cooling. This method is recommended because evaporation is one of the most effective ways to help lower your horse's body temperature during hot weather.
Don't forget your horse's gut health
Summer management often means changes to routine:
- Travelling
- Competitions
- Richer grazing
- Less turnout
- Different forage
- Increased stress
All of these can negatively influence the hindgut microbiome. Because over 70% of the horse's immune system is associated with the digestive tract, maintaining a healthy gut becomes particularly important during periods of increased challenge.
Supporting microbial diversity with a fibre-rich diet and prebiotic nutrition helps maintain digestive stability when routines inevitably change.
Many owners notice loose droppings, faecal water or changes in appetite during busy summer periods, often reflecting the combined effects of heat, travel and stress rather than one single cause. Feeding a quality hindgut supplement like Gut Food (or UltraMet for good doers) helps provide the hindgut with a variety of prebiotic fibres that it needs to feed the good bacteria. Horses under heavier workloads and more stressy types may benefit from additional gastric support, in those cases Ulceraid is recommended as it supports both the stomach and hindgut for optimal health.
Why is my horse coughing when the pollen count is high?
Hot weather isn't just about temperature.
Periods of high pollen, dry ground and increased dust can all affect your horse’s respiratory comfort. Poor air quality can place additional demands on the respiratory system, particularly for horses already prone to coughing or with pollen/environmental sensitivities.
Simple management changes can help:
- Feed damp hay if appropriate.
- Improve stable ventilation or increase turnout time as appropriate.
- Avoid sweeping while horses are inside.
- Reduce exposure to dusty arenas where possible.
- Monitor local pollen and air quality forecasts during peak periods.
Supporting respiratory health becomes especially important for competition horses working harder in challenging environmental conditions. We have a useful article on horse respiratory health that you can read here for additional support.
Should I keep my horse stabled or turned out during hot weather?
Whether you should keep your horse in or out during hot weather is one of the biggest dilemmas and most asked questions this summer! There is no simple answer to that question as the correct answer will depend on your individual horse’s environment. However, no matter if your horse lives out or is stabled during the day, providing opportunities to escape direct sunlight in hot weather is essential.
If turned out:
- Ensure access to natural or artificial shade.
- Check water supplies frequently.
- Consider overnight turnout during heatwaves if appropriate.
- Choose breezier paddocks where possible.
- Poo pick regularly to help reduce flies
If stabled:
- Maximise airflow.
- Open doors and windows safely.
- Use fans where appropriate.
- Avoid allowing stables to become excessively warm. Wooden stables in particular become much warmer than block stables, particularly those with limited ventilation.
Every horse is different, so management should always be adapted to the individual’s needs.
Best ways to reduce flies around horses
Flies are inevitable around livestock and horses but you can do your bit to help reduce the numbers and the impact they make on your horse. Excessive amounts of flies can cause horses to become agitated, stressed and uncomfortable, sometimes running around to try and escape them. In hot weather that is added stress and heat build-up they don’t need! You can help to reduce fly numbers by regularly poo picking their paddocks and removing any stagnant standing water. A healthy gut can also help in reducing your horse's fly magnet status, read more here.
Should I use a fly rug in hot weather?
The lightweight mesh fly rugs available on the market create a barrier against biting insects to try and reduce the discomfort for your horse. However in the hot weather even these lightweight rugs can be too much and cause overheating, reducing their comfort. Using a good quality fly repellent, a fly rug and/or a fly mask can help to reduce the stress but the level of protection required will depend on your individual horse’s needs and their environment.
How to spot early signs of Heat Stress
Most horses cope remarkably well with warm weather, but recognising early warning signs is important.
Keep an eye out for:
- Excessive or prolonged sweating
- Rapid breathing
- Slow recovery after exercise
- Lethargy
- Reluctance to work
- Reduced appetite
- Poor performance
- Changes in behaviour
If your horse appears to be struggling, stop exercise immediately, move them somewhere cool, provide access to cool clean water for drinking, begin active cooling and continue until their rectal temperature drops and they begin to stabilise. Always contact your veterinary surgeon if they fail to improve or you are concerned.
Read our full article on heat stress in horses – causes, signs and how to prevent it.
Summer Management Is About Preparation, Not Perfection
You don't need an elaborate routine to help your horse cope with summer.
Focus on the fundamentals:
- Unlimited fresh water
- Replacing electrolyte losses after sweating (ideally feeding in advance to replenish losses as they occur)
- Exercise during cooler parts of the day
- Support digestive health during changes in routine
- Monitor respiratory comfort as pollen and dust increase
- Provide shade and good airflow
- Learn to recognise early signs of heat stress
When these foundations are in place, both you and your horse are far better equipped to enjoy everything summer has to offer – together! A little advance planning now means they can feel and perform at their best when it matters most.
The Equell Team, 2.7.26
References:
- US Equestrian (USEF) – Heat Alert: Clarification and Recommendations for Competitions (2024)
- Fédération Equestre Internationale (FEI) – Beat the Heat
- Kang H. et al. (2023). Heat stress in horses: A literature review. International Journal of Biometeorology.
- Verdegaal, E.-J.M.M., et al. (2020). "Effects of Pre-Cooling on Thermophysiological Responses in Elite Eventing Horses." Animals https://pmc.ncbi.nlm.nih.gov/articles/PMC7552184/
