You may think that you are doing your dog a favor, but actually it is not very good idea!
A dog’s coat is an insulation which helps your dog when it is too cold, but also when it is too hot.
Dog’s coat has several layers, and these layers are essential for thermoregulation . Also, coat will protect skin from sunburns.
If your dog has longer hair some trimming should not be a problem. It is best to allow a professional groomer to perform the trimming, and never shave down to the skin.
If you prefer not to cut your dog’s hair, that’s also fine. Dogs with thick coats naturally shed so that they have a lighter coat in the summer. Remember to brush your dog’s fur because clean, brushed fur allows for better air circulation.