The willing retriever is his own worst enemy
A Golden Retriever's heatwave risk comes less from his coat than from his character. This is a dog bred and born to retrieve as long as anyone will throw, to swim whenever water appears, and to stay cheerful through discomfort that would make another breed quit. In serious heat that willingness becomes the hazard: he will chase a ball on a hot afternoon with the same joy as on a cool morning, while his temperature climbs past the point his panting can control. Your job through a heatwave is to be the judgement he does not have, rationing the games he would never ration himself.
Keep the coat, lose the loose undercoat
Do not shave or clip a Golden's double coat short for summer. The outer coat and undercoat together insulate against heat reaching the skin and protect that pale skin from sunburn, and a shaved Golden is more uncomfortable, not less. What helps is thorough, regular brushing during the heatwave to remove the loose undercoat he is shedding, so air can circulate through the coat that remains. Pay attention to the dense feathering on his chest, belly and legs, where shed hair mats and traps warm, damp air against the skin.
Rework walks and games for the heat
Walk early and late, favour shaded and grassy routes, and keep sessions unhurried. Replace the long midday fetch game with short morning retrieves, sniffing in shade, and indoor puzzle play, and let him paddle or stand in a shallow pool if he enjoys water, with supervision as you would give any swim. Test pavements with the back of your hand before walking on them, remember that a wet dog on a hot drive home still needs a cooled car, and never leave him in a parked vehicle while you shop. On the very hottest days, a toilet break and a quiet house are a complete and responsible exercise plan for this breed.
The damp-coat problem after cooling off
Goldens love water so much that heatwave cooling often creates its own skin trouble. A coat that stays damp for hours, especially under the ears, around the collar and in the armpits, can develop hot spots: sore, weeping patches that appear fast and bother the dog intensely. Rinse river or paddling water out of the coat, dry him thoroughly down to the skin after every swim or soaking, and remove a wet collar until he is dry. Check daily through the heatwave by running your hands through the coat, because your fingers will find a warm, tender patch before your eyes spot it in all that fur.
Recognising overheating in a cheerful dog
Do not let a wagging tail reassure you out of what the rest of him is saying. Heavy, relentless panting, thick drool, a very red tongue, slowing down mid-walk, seeking shade and lying flat, vomiting or wobbliness are all stop-now signs in a Golden. Move him into shade or indoors, wet his belly and chest with cool water, offer small drinks, and call your veterinarian if he is not clearly recovering within minutes, or immediately if he collapses or seems confused. Older Goldens, overweight dogs and those with known heart or breathing issues should be treated as high risk throughout any hot spell.
Agree the heat rules once, for everyone
Golden Retrievers usually have several admirers in a household, and each one is a potential extra walk or bonus fetch game on a day when he has already had his ration. Agreeing the heatwave limits openly stops well-meant kindness from adding up to an overheated dog. KinsLe Family Sharing holds your Golden Retriever's walk times, fetch limits and swim-and-dry rules on his shared profile, so every family member and visitor plays by the same heat plan.