Why is my dog not eating in hot weather? (2026 vet advice)

Let's answer the question you came here for

Yes, dogs often eat less during the summer months. A six-year study on cats found that their food intake dropped by around 15% in warmer months — researchers believe this is linked to changes in temperature and daylight hours. While there is no direct equivalent study for dogs, the same seasonal logic applies: when it is hot, appetite drops. This is a normal physiological response.

But eating less is not the same as eating nothing at all. That is the distinction you need to understand.

Why do dogs eat less in summer?

Digesting food creates heat. When the weather is already hot, a dog's body instinctively reduces any activity that generates more heat — including digestion. Eating less means creating less heat, which means staying cooler.

Several other factors also come into play:

1、Reduced activity levels: On hot days, dogs prefer lying in the shade to running around. Fewer calories burned means fewer calories needed.

2、Hormonal changes: Longer daylight hours and rising temperatures can affect hormone levels, slowing digestion and extending the feeling of fullness.

3、Instinctive regulation: Just like humans, dogs naturally eat less when their bodies are managing heat stress.

Vet Brian Faulkner from Petplan also notes that dogs typically eat more in winter because they need extra energy to keep warm. Summer is the opposite — they simply do not need as much energy.

Signs that it is normal — nothing to worry about

If you notice any of the following, the change is likely just heat-related:

1、Eating less but still eating — not refusing food entirely, just eating smaller amounts

2、Still interested in treats and toys — if they won't even touch a treat, that is a different story

3、Energy levels are normal, still responsive — they may seem lazy, but they still react when called

4、Eating more during cooler hours — better appetite in the early morning or late evening

5、Skipping one meal but eating the next — missing one meal occasionally is not a concern

Petplan advises that if your dog is eating less but maintaining a stable weight and still showing interest in food, there is usually no cause for concern. You can reduce each meal by 10-15% rather than forcing them to finish the full portion.

Signs that you should call the vet

Vet Shaun McCormack has pointed out that a dog not finishing their bowl is one of the key warning signs to watch for in summer. The following should not be dismissed as "just the heat":

Contact your vet if you notice any of these:

1、No food for more than 24 hours (puppies need even more attention — toy breeds should not go beyond 12 hours)

2、Won't even touch their favourite treat — this is one of the most telling signs

3、Lethargy or unusual tiredness — not just "lazy," but a noticeable drop in energy

4、Vomiting or diarrhoea

5、Noticeable weight loss

6、Pale gums or rapid breathing — these may point to more serious health issues

The PDSA advises: "If you notice a change in your dog's eating habits, contact your vet as soon as possible. If your dog has not eaten for more than 24 hours, it is important to seek veterinary attention promptly."

Other possible reasons for reduced appetite

Summer appetite loss is not always just about the heat. According to vets and pet nutrition experts, other factors can play a part:

1、Slower digestion: Higher temperatures and longer daylight hours can slow down a dog's metabolism, meaning food stays in the system longer and the feeling of fullness lasts more.

2、Travel or disrupted routines: Holidays, guests, or boarding can all increase stress levels and affect appetite.

3、Too many treats or table scraps: Summer barbecues and social gatherings mean more human food is being offered, which can reduce a dog's interest in their regular meals.

4、Puppy-specific issues: If your dog is still young, teething discomfort or other health issues could also be affecting their eating.

What you can do — 5 practical tips

If you have confirmed that your dog is just "not hungry because of the heat" rather than being unwell, these steps can help:

1、Adjust feeding times
Move mealtimes to the early morning and late evening, when temperatures are lower. Vets also recommend splitting the daily portion into 3-4 smaller meals — smaller, more frequent portions are often more appealing than one large bowl.

2、 Add wet food or water
Adding water, unsalted broth, or switching to wet food increases moisture intake and makes the food smell stronger, which is more tempting for dogs. Dry food can also lose its freshness more quickly in the heat.

3、Keep the bowl in a cool place
Place the food bowl in a cool, shaded area indoors. Bowls left in direct sunlight can heat up, causing the food to spoil or become unappealing. Metal or ceramic bowls can also become uncomfortably warm to the touch.

4、Make frozen treats at home
Freeze dog-safe ingredients like plain yoghurt, blueberries, cucumber, or banana into ice cubes. These help with cooling and provide extra hydration.

5、 Stay consistent, reduce stress
Even when travelling, try to keep feeding times and locations as consistent as possible. Dogs are creatures of habit — a disrupted routine can affect their appetite as much as the heat.

Summer food safety reminder

Dog food can spoil more quickly than you might expect in hot weather.

Bacteria grow faster in high temperatures. If your dog has not finished their bowl within 45 minutes, throw the remaining food away rather than saving it for later. Dry food should also be stored in a cool, dry place away from moisture. A dog's nose is very sensitive — if the food smells off, they will not eat it. That is not pickiness; it is self-protection.

A simple rule to remember

If we had to sum it up in one sentence:

Eating less + normal energy + stable weight = probably fine

Eating nothing + low energy + other symptoms = call the vet

You know your dog better than anyone. If they are eating less but still acting like themselves — relax, and let the summer pass. But if they won't touch their favourite treat and have not eaten for more than 24 hours — do not wait. Call your vet.

More summer dog care guides

If you found this helpful, you might also want to read:

2026 UK Heatwave: Dogs Have Only 30 Minutes in a Heatstroke Emergency – Can You Spot These 5 Signs?

2026 UK Extreme Heat Alert: Summer Dog Walking – Avoid These 3 Time Slots

References

1、The Mirror. 'As a vet this is the first sign something is wrong with your dog'. July 2024

2、Daily Record. Vet says to watch dogs for one change in hot weather. July 2024

3、Liverpool Echo. Vet shares 'key' sign something is wrong with your dog in the heat. July 2024

4、Petplan. Do dogs eat less in summer? Expert vet advice

5、Tractive. Summer Dog Food: How To Keep Your Buddy Cool & Well-Fed

6、Bella+Duke. Do dogs eat less in summer?

7、Natures Menu. Do dogs eat less in summer?

8、Great Pet Care. Puppy Not Eating: Causes and What to Do

9、Tails.com. Why is my puppy not eating?

10、CESAR. 6 Reasons Why Your Puppy Isn't Eating

11、PDSA. My dog isn't eating properly