Dogs love warm weather, but they do not handle heat the way people do. They cannot sweat all over their bodies, and they cannot always tell us when they have had enough. Overheating can start quietly — a little extra panting, a slower walk, a search for shade — and build quickly if those early signs are missed.
This guide covers 10 warning signs, what each one can look like, and what to do in the moment. It is not a medical guide and does not replace a vet; think of it as a practical checklist that helps you notice trouble sooner and act calmly.
1. Heavy, Fast Panting That Does Not Slow Down
Panting is normal. It is one of a dog’s main ways of releasing heat, and you will see it after exercise or on a warm day. The warning sign is panting that looks different from your dog’s usual pattern: very fast, loud, or shallow panting that keeps going long after your dog has stopped moving and had a drink.
Learn what your dog’s normal panting looks like, so you notice changes sooner. If you are unsure whether panting is normal or a warning sign, our guide on why your dog may be panting so much can help you compare common causes.
What to do: move your dog to shade or indoors, offer small amounts of cool (not ice-cold) water, and let them rest. Do not force them to keep walking or playing.
2. A Tongue and Gums That Look Unusually Red or Dark
A healthy dog’s tongue and gums are usually a soft pink. When a dog is overheating, they may look bright red, dark red, or even slightly purple. Later, the gums may look pale or grey, which is also a concern.
Gently lifting your dog’s lip now and then helps you learn what “normal pink” looks like for them, so a change on a hot day stands out.
What to do: if the colour looks very different from normal, stop all activity, cool your dog gradually, and contact your vet for advice. Colour changes in the gums are one of the signs vets take seriously, so do not wait it out.
3. Drooling More Than Usual
Some breeds drool naturally, especially large dogs with loose lips. The warning sign is drooling that is heavier than your dog’s normal level, or drool that looks thick and sticky.
Thick, ropey saliva can appear when a dog is struggling to cool down, along with frequent lip-licking.
What to do: offer water, move to a cooler spot, and watch closely. If drooling continues along with heavy panting or weakness, treat it as a warning sign and seek vet advice promptly.
4. Slowing Down, Lagging Behind, or Refusing to Walk
Dogs are often eager to please, and many will keep walking even when they are uncomfortable. Watch for a dog that suddenly slows down, stops often, lies down on the grass, or pulls toward shade. A dog that refuses to keep walking is not being stubborn — they may be telling you they need a break.
Puppies, older dogs, and overweight dogs may tire faster in heat, but any dog can reach their limit on a hot or humid day.
What to do: stop immediately. Do not drag your dog along or encourage them to “push through.” Let them rest in the shade, offer water, and head home once they seem steadier. If they cannot stand or walk normally, call your vet right away.
5. Seeking Shade, Water, or Cool Surfaces
Dogs are good at finding comfort when they can. A dog that keeps moving into shade, lying on cool tiles, or trying to lie near a water bowl is often trying to cool down.
On its own, this is not always a warning sign — many dogs simply enjoy a cool spot. It becomes a warning sign when it is urgent or constant, or when it comes with other signs on this list, like heavy panting or drooling.
What to do: help them out with shade, a cool resting spot, and fresh water. A damp towel on the floor, a fan, or a cool room can all help. Do not leave your dog to “sort it out” alone in a hot garden.
6. A Dry Nose, Dry Mouth, or Signs of Dehydration
Panting uses up moisture, and an overheating dog can become dehydrated. Signs can include a dry nose, dry or sticky gums, or sunken-looking eyes.
Not every dry nose means trouble — noses dry out for many harmless reasons, including sleep and dry air. The concern is a dry mouth or nose combined with other heat signs, or a dog that seems dull and uninterested in water.
What to do: offer small sips of water often, rather than a huge bowl all at once. If your dog will not drink, or seems very weak, contact your vet. Do not force water into a dog’s mouth.
7. Wobbliness, Weakness, or Stumbling
A dog that seems unsteady on their feet, stumbles, sways, or has trouble standing up is showing a serious warning sign. Weakness in the legs, a wobbly walk, or collapsing needs urgent attention.
This sign can appear when overheating has progressed further, so it should never be brushed off as tiredness. Older dogs and dogs with existing health problems may be more vulnerable, but wobbliness in any dog on a hot day is a red flag.
What to do: stop all activity, move your dog to the coolest spot available, start gentle cooling with damp towels on the belly, neck, and paws, and call your vet or an emergency clinic immediately. Keep your dog as calm and still as possible while you get help.
8. Vomiting or Diarrhoea
An upset stomach can have many causes, but vomiting or diarrhoea on a hot day, especially alongside panting, drooling, or weakness, can be linked to overheating. If it happens during or after heat exposure, watch your dog closely, even if they seem fine afterwards.
What to do: keep your dog cool, offer small sips of water, and contact your vet for advice — especially if vomiting happens more than once, if there is blood, or if your dog seems weak or confused. Do not give human medicines.
9. A Racing Heartbeat or Rapid Breathing at Rest
Place your hand gently on your dog’s chest while they are resting. If their heart seems to be racing, or their breathing is fast and shallow even though they have been resting for a while, that is a warning sign.
Normal resting rates vary by size — smaller dogs tend to have faster heartbeats than larger dogs — so knowing your dog’s normal rhythm helps. The key change is a rate that stays high long after exercise has stopped.
What to do: keep your dog resting in a cool place, avoid excitement or further activity, and call your vet if the rapid rate does not settle or comes with other warning signs.
10. Confusion, Glassy Eyes, or Collapse
These are the most serious signs, and they mean your dog needs urgent veterinary help. A confused dog may stare blankly, seem disoriented, bump into things, or not respond to their name. Their eyes may look glazed or unfocused. In the worst cases, a dog may collapse, have a seizure, or lose consciousness.
Possible causes of collapse in the heat include heatstroke, which is a medical emergency that can develop quickly.
What to do: call your vet or an emergency clinic immediately. While you wait, move your dog to shade, cool them gently with damp towels on the belly, neck, armpits, and paws, and offer small sips of water only if they are conscious and able to swallow. Do not use ice water or ice baths, and do not delay the vet visit to try home cooling alone.
How to Cool an Overheating Dog Safely
If you spot warning signs, move to shade or indoors straight away. Offer cool water in small amounts, wet the belly, neck, armpits, and paws gently with a damp towel or lukewarm water, and use a fan if you have one. Keep your dog calm and still, then call your vet — even if they seem better, a quick call helps you decide whether a check-up is needed. Avoid ice baths and ice-cold water, which can shock the body.
Everyday Prevention: Keeping Your Dog Cool in Summer
Walk at cooler times — early morning and late evening are best. Test pavement with your hand: if it is too hot for your palm, it is too hot for paws. Never leave a dog in a parked car, even with windows cracked, as a car heats up dangerously fast. Always provide shade and water, and skip intense exercise on hot days. Regular brushing helps air flow through the coat, but do not shave a double-coated dog without vet or groomer advice.
Watch humidity, not just temperature: humid days make panting less effective. Loud gatherings can also add stress on top of heat, so it helps to know how to keep your dog calm during fireworks and holiday parties before the busy season. Our guide on how to prepare your dog for winter and cold-weather walks covers the other end of the year.
What NOT to Do
Good intentions can sometimes cause harm. Do not leave your dog in a hot car, even briefly, or force them to keep exercising if they stop or lie down. Do not use ice water or an ice bath, and do not cover your dog with a soaking-wet heavy blanket — a damp towel, replaced regularly, is better. Do not force water down their throat, as this risks choking, and do not give human medicines. Do not assume a dog is fine because they are still wagging, and do not wait for every sign to appear: one or two clear warning signs are enough to stop, cool, and call for advice.
When to See a Vet
Contact your vet promptly if your dog shows heavy panting that does not settle after rest and cooling, wobbliness, weakness, stumbling, or collapse, vomiting or diarrhoea alongside heat signs, gums that look very dark red, purple, pale, or grey, confusion, glassy eyes, seizures, or loss of consciousness, or a dog that will not drink or seems very dull and unresponsive. If in doubt, call — any sign that worries you is reason enough.
For serious signs such as collapse, seizures, or unconsciousness, treat it as an emergency. When you call, describe what happened, how long your dog was in the heat, and which signs you have seen. Even if your dog seems normal again, a vet check is often wise, since some effects are not visible from the outside. Never try to diagnose the problem yourself, and never delay a vet visit because a home remedy seems to be working.
FAQ
How do I know if my dog is just hot or actually overheating?
Normal heat is light panting after play that settles within a few minutes of rest, shade, and water. Overheating is panting that stays heavy, drooling, weakness, wobbliness, or a change in gum colour. If several signs appear together, or one is severe, stop activity, cool your dog gently, and call your vet.
Can a dog overheat indoors?
Yes. A hot, stuffy room or a conservatory in direct sun can be risky, especially for flat-faced, older, or overweight dogs. Keep rooms ventilated, with fresh water and a cool resting spot.
How long does it take for a dog to overheat?
It varies a lot. Some dogs can overheat in as little as 10–15 minutes of intense exercise on a hot day. Humidity, direct sun, and lack of water speed things up, so there is no single safe time limit — watch your dog, not the clock.
Should I pour cold water on my overheating dog?
Use cool or lukewarm water, not ice-cold water. Wet the belly, neck, armpits, and paws with a damp towel or gentle pouring, and use a fan if you have one. Avoid ice baths, which can shock the body. The goal is gradual cooling while you contact your vet.
What is the first thing I should do if I think my dog is overheating?
Stop all activity, move your dog to shade or indoors, offer small sips of cool water, and start gentle cooling with damp towels. Then call your vet for advice. For serious signs like collapse or confusion, call an emergency vet clinic straight away and keep cooling gently while you get help.
Conclusion
Your dog trusts you to notice what they cannot say. Learning these 10 warning signs gives you the chance to step in early, when help is simplest. Most hot days will pass without trouble if you walk at cooler times, carry water, and give your dog shade and rest. But when something feels off, trust that feeling: stop, cool, and call your vet. A calm, quick response can make all the difference.