It's not just dogs, its all mammals, humans included!
Dogs and cats can eat up to 15% less in hot weather so don't worry. Going off food in hot weather is totally normal. When temperatures rise dogs tend to laze around much more and therefore use less energy. If less energy is used, then less food is required to product the energy.
Daylight also has a part to play. Increased daylight hours alongside higher temperatures have been found to cause hormonal changes which result in a slower metabolism. See here.
Ways to help:
- Feed earlier in the day or late at night when its cooler.
- Decrease the amount of food offered as required.
- Try not to stand over them as they eat. Your stress is transmitted to your dog and will stop them from eating.
- Don't be tempted to start switching the food, as this just encourages fussy eating.
- Avoid giving treats. If you're worried your dog isn't drinking enough then maybe try some frozen bone broth. Highly nutritious and also cooling.
If your dog changes behaviour or starts to pant excessively seek veterinary help.