Is it normal for dogs to be less hungry when it's hot?

Your dog is just like you -- will eat when he or she is hungry. It's great he is hydrating often.

Yes, it's normal, as long as he's eating his normal AMOUNT is all that matters.

So...

If he normally eats 3 large meals a day, but is now eating 6 smaller meals...he's fine.

If you have him on a schedule where you feed him 1 cup of food per day (small dos, 1/2 cup morning, 1/2 cup at night) and he normally wolfs them down each feeding, but now he's eating that 1 cup over the entire day instead...he's fine.

The time to worry is when he's NOT eating as much in a day as normal....and/or if he's not drinking.

Also remember, do NOT put ice in his water dish. Just make sure when you fill his bowl that the water is as cold as possible from the tap. To help cool him off - if he likes it - give him a bath with lukewarm water or let him play in a hose, or even buy him his own sprinkler if you've got a decent sized yard.

Yes, that is normal. dogs will drink more but eat less in hot situations.

Yes

Yes I have definitely seen that recently.