Dogs should never be left in a car on a hot day - even in the shade or with windows open. If you are taking the dog on a car journey try to avoid traveling during the hottest part of the day. Ensure the dog is not in direct sunlight, and take plenty of water. On long trips, stop frequently, they should be drinking little and often, not gulping large quantities. Never allow your dog to hang their head out of the window when driving.
Dogs shouldn't be walked during the hottest part of the day, morning and evening are preferable. Try to find shady areas to walk your dogs, avoiding hot pavements which may burn their paws, and carry water. Dogs benefit most from little and often, so lots of pit stops and do not walk as far as on cooler days. Try to avoid using water bowls left out for dogs in parks, because this can unfortunately spread disease.
During the day at home, most double glazing can be locked in the "ajar" position to allow for fresh air and to catch any breeze, but still be secure (and won't void your insurance!) or try moving the dogs to another area if necessary. A plastic bottle of tap water can be frozen, wrapped in a tea towel and left for your dog to lie against if they wish to - this tip can also be used for rabbits and other pets.
Dogs must be able to move out of a hot environment into a cooler one, as this makes their panting more efficient at cooling them down, so leave doors open in the house if necessary. Bathrooms and kitchens can be a popular choice for pets, as the floor is often much cooler for them to lie on.
Short-nosed, black and long-haired breeds, or overweight dogs can suffer more from the heat. If they get too warm, soaking them in cool (not cold) water and rubbing it right down to the skin is more beneficial than covering them with a wet towel. Don't forget underneath as well, the groin and 'armpit' area, as this is where most cooling will occur - lying down in shallow water is a great way to cool off. Don't over-estimate your dog’s fitness level and decide to walk for much longer than normal because the weather is hot - this can put an unfit dog at risk of heat stroke.
Evidence is still scarce on the benefit of 'cooling coats', but studies seem to indicate they affect core temperature most when dogs have finished their walks and need to cool down afterwards. During the walk there appears to be little difference.
White dogs, cats and rabbits (or with white patches in sensitive areas) can get sunburn on ears, nose and around the eyes. Pet sunscreen is very rare, and hard to get hold of (products may be different for different species), so speak to your vet to see if they recommend a sunscreen - check with your insurance company that they will be covered if they have a reaction or lick it off. If your pet sunbathes on its back the stomach is at risk of burning, so keep them in the shade. Avoiding the sun is preferable.
Make sure your dog always has a good supply of drinking water, in a weighted bowl that can't be knocked over. It's recommended to leave out more than one bowl, as some dogs will not drink once the level drops a certain amount, or they may try 'paddling' in the water and foul it with dirt from their paws. Don't restrict water on very hot days – you may need to encourage breaks in drinking to avoid vomiting it back up or the risk of bloat, but otherwise allow your dog free access. Helping your dog keep cool before they overheat is essential.
Grooming regularly helps to keep the coat free from excessive fur, and means it will be more able to keep your dog cool. It also means less fur on the floor! Clipping longer coats back to the skin can in some cases make your dog hotter as they've lost the layer of cooler air that their fur traps against their skin.
Muzzles - even basket muzzles restrict the dog's ability to pant effectively, and muzzles that prevent the dog from opening its mouth can be dangerous if the dog is hot. If the dog needs a muzzle for their walks, it's better to take them early or late in the day, or not walk them at all.
If your dog dangerously overheats and collapses - cool your dog as fast as possible. The longer the dog is dangerously hot, the greater the damage. Use any reasonable cooling method available. Ice packs, ice water and ice water soaked towels are the best methods and has no side effects (whereas a dog remaining hot CAN cause significant damage/death). You want the dog wet and you want to increase cool air flow over the dog if possible to use evaporation cooling. Cool the dog first, then transport unless you can cool during transport to the vet.
Other Summer Risks:
Watch out for ticks while walking in long grass or meadows especially if there are horses or livestock nearby. These can be removed with a special "tick tweezer". Avoid smothering or burning the tick as this can cause it to release saliva or stomach contents, raising the risk of infection. Grass seeds can be a real hazard as if they find a break in the skin they can work their way inside your dog, so check paws, eyes and ears if they seem irritated, a vet visit may be needed to remove them.
Bee stings - remove the sting by scraping it with a hard object, avoid using tweezers as this can lead to more poison entering your pet. Bathe with bicarbonate of soda and water, also an ice pack can relieve pain. Wasp stings - bathe the area with vinegar. There will be some swelling, if this is excessive, or inside or around your dog's mouth a vet check may be needed as pets can be allergic to stings in the same way humans can, and swelling can block the airway.
Leaving windows open on the top floor can be hazardous to cats - they often land on their feet, but this can be followed by their jaws and teeth, which may then need medical attention.