Why does my dog eat less in hot weather

Digestion produces metabolic heat as a byproduct, and on a hot day a dog's body has less incentive to take that on, similar to people eating lighter meals in summer than winter. Reduced activity in the heat also means fewer calories burned and less hunger overall.

Feeding during the cooler parts of the day, early morning or after sunset, splitting the daily food into smaller portions, and offering a slightly cooler or wetter version of the meal can all help maintain adequate intake during a hot spell.

A drop in eating that is dramatic, that comes with panting at rest, lethargy, or vomiting, is more likely heat stress or another issue than simple seasonal appetite dip and needs prompt attention rather than waiting it out.

A dog eating less in hot weather often needs closer attention to water intake as well, since less food, particularly wet food, means slightly less moisture coming from the diet at exactly the time of year when overall hydration needs are highest. Checking that fresh, cool water is always available in more than one spot around the home, and topping up a travel bowl on any outing, helps offset the smaller contribution from a lighter summer appetite. Adding a splash of water to dry kibble during the hottest weeks is a simple way to combine both the moisture and the more appealing softer texture in one step.