
I'm going to differ from the others and this is based to our own experience with a different breed.
Our old Leo was MUCH cooler in her clipped summer coat than with her coat on!
So the coat keeping her cool definately did not work with her, maybe hers was not thick enough to keep her cool but thick enough to make her very warm...
She would be so much cooler and more lively/happy after her coat was clipped off and her panting would definately be a lot less when clipped.
We did not clip her because of not wanting to look after her lovely thick coat or anything.
To be honest the summers we clipped her I felt sad as I love crooming and love dogs to look nice and obviously full coat would be part of it but I could see the benefit for her so there were no question if I would have done it for her.
Main reason she was first clipped was because she could not swim in full coat and loved swimming!
She had immune problems and very sensitive skin and would get hotspots in the summer just from drinking and then getting the cheeks wet from sleeping on the water she dribbled on the ground! No matter how well we through blowed her dry, she would still get problems and at least with short coat the reddening of the skin got spotted and treated before full blown hotspots.
So one year we decided to clip and see if she could then swim more often and not get hotspot, meaning she could do what she loved doing and enjoy her life more...
Worked for us!
This is only our own experience with one dog and coat type, she was the only one we have ever clipped and she definately benefitted from it.
The clipping did not spoil her coat either, which is what some people say...
It grew back just like it had been before, every winter she would sport lovely thick wintercoat.
She did have quite fluffy coat (not correct kind in my opinion) even before clipping, hers was nearly like a coat of a spayed girl but due her other problems she stopped having seasons for few years so obviously her hormones were a mess...
So I don't know if it would have made a difference to other kind of coat and spoil it, to hers it made no difference at all.