Unlike humans dogs don’t have the ability to sweat all over. They do have sweat glands on their paws, but this is where the sweating stops. Instead dogs will loll their tongue out and pant to cool down.
A hot dog cooling down by jumping into a nice cold lake
In hot weather is can be very easy for your dog to overheat so it is important you take measures such as providing shade or a wet towel for your dog to cool down and provide plenty of fresh drinking water. It is also wise to avoid taking your dog for long walks in the middle of the day during hot weather.