As the weather's heated up with summer well underway, it's important to remember that just because our pets are better suited to the heat than us, they aren't immune from it's effects. The most well-known danger is leaving pets in vehicles on warm sunny days. Short-snout breeds in particular suffer when left in a hot car, but all breeds are affected. Even cracked windows don't completely mitigate the effects. A car can reach up to 50 degrees higher than the outside air on a warm day in just a handful of minutes. The hotter and sunnier the day, the quicker the car gets there. To mitigate this, please consider leaving your pet at home unless the trip is about them (vet visits, going to the dog park, and the like). Never leave your pet out in the car alone, and when you park, invest in a sun shield, crack the windows, and if possible, park in the shade. That way when you get back in the car the heat box effect shouldn't be as drastic.
But cars aren't the only danger in hot weather. Just like us, our pets can dehydrate a lot faster in the heat and humidity. Make sure they have plenty of fresh, clean, and cool water to try and mitigate this. And again, much like us, their feet and bodies are sensitive to the heat. Dogs have a better tolerance, but not by much. If your feet hurt after standing on the sidewalk for a short period of time, it's likely doing the same to your pet. If you take a walk when the sidewalk's hot, keep moving and try and walk in areas with accessible grass so your pet has a softer and cooler alternative to the asphalt.
There is one big never-ever rule for dogs: Never shave their coat. Keep it free of build up by grooming it regularly and depending on the breed, get your pet a trim, but their fur protects them from harsh sunburns and in some breeds such as huskys, their summer coat is actually designed to help keep them cool. A dog's fur is not like our clothes, their bodies know what they're doing, we can just help give it a boost to work at its most efficient with a little maintenance work.
These will all help prevent your pet from succumbing to the heat, but it's also important to know the warning signs if they still do. Heavy "panting, lethargy, drooling, fever, vomiting, and collapse" are all symptoms of heat stroke and if you witness them, get to the vet as quickly as you can to prevent permanent damage.
Keep you and your pets safe while having fun this summer. Enjoy the weather!