It has been quite hard for all our pets in this weather. As you have identified the most important thing is not to insist your dog takes a walk in the heat of the day. I’m afraid it is a case of walking them very early, or as it cools off in the evening. If this is not possible, it is safer not to walk them at all and to find other ways to wear your dog out at home.
Allow your dog to find their own spot, where they feel most comfortable. This may be a shady spot in the garden, or a cool tiled floor in the kitchen. Make sure they have plenty of water to drink, and some dogs may appreciate being sprinkled with water or having damp, cool towels placed over them. If you can, and your dog is adventurous – you may wish to consider giving them access to a ‘doggy paddling pool’. If your dog has a very thick coat, you may want to consider getting it clipped for the summer. Some dogs also enjoy their own version of an ice lolly to cool down. You can make these by filling a favourite treat ball or similar with flavoured water (a few drops of gravy will make it tasty) and then freezing it overnight. It will make a mess though so it might be wise to encourage your dog to eat it outside!