Does Jack have a thick undercoat? Has he started to shed yet? Does he shed a lot?

Should he get a Summer haircut? I have seen Goldens who do and sometimes it helps and sometimes not. However, if they have sufficient undercoat, that should not be necessary. I have also seen a Golden that does not shed at all and is unable to keep themselves cool because of it. The owners of this dog have to take extra measures during heat to keep the dog cool.

Some things to try before the haircut. Cool the dog down before any outside activity. Never wet the dogs back but thoroughly wet down the stomach and feet. Water on the dogs back will attract the sun and will just evporate. Dogs sweat from their pads and tongue. Keep plenty of icey cold water in a bottle and occassionally squirt the dogs pads and let him drink for a second. They do not perspire from their skin like humans. Another option is they now sell Cool pads that you can use to wrap around the dog. I've never tried one but hear they work really well.