~We NEVER recommend shaving your Newfoundland to the skin unless it is for medical reasons or extreme matting~
The Newfoundland has a double coat consisting of a top layer of long coarse hair and a soft, dense, shorter undercoat. The undercoat is oily, which repels water and helps to keep the EXTREME COLD and HEAT away from the dog's skin. We do NOT recommend shaving a Newfoundland in the summer. You run the risk of SUN BURN and the dog is at a greater risk for a SUN STROKE. They need their coat for protection.
The Newfoundland "blows" its coat usually in the springtime. You may find it coming out in clumps. At this stage it will take some time and patience to get the coat combed out. After you succeed in accomplishing this job, a good weekly brushing should keep the coat looking nicely. Brushing more often during the week will keep the loose hair off your floors, furniture and clothing better.
In the summer and in warm climates (even NY state gets very hot during the summer), if you really feel you must do something with your Newfoundland's coat, you may have a groomer give the dog a summer cut. Never shave a Newfoundland because shaved skin can sunburn. A licensed groomer will take off just enough to cool your dog and leave enough hair to protect the skin AND the undercoat. Cutting short all over with a 4 blade or using an F comb (ask your groomer for this) is a much better alternative to shaving to the skin, especially if you have a Newfie with a VERY thick coat (coat thicknesses can vary). If you have a groomer that insists on only shaving to the skin and not being able to "trim" the coat a little, then I think it is time to find a new groomer.
In warm weather and climates have some alternatives that will help keep your Newfie cool. If you have air conditioning, only do walking or playing in the early morning or later in the evening, with short trips out during the day to "potty". Install ceiling fans, have plenty of room fans and bowls of water handy. Take them swimming, keep kiddie pools and sprinklers in your yard. Remember, if it is too hot for YOU to be outside for any length of time, it is too hot for them too.
And, for those who insist on cooling your Newf, clip the hair on the tummy - so they can make better contact on cool floors.