South Bay summers get genuinely hot inland, and every year we are asked to shave double-coated dogs down to the skin to help them cope. It is a completely understandable instinct, and for those breeds it usually makes things worse.
Why shaving a double coat backfires
A double coat is not a single layer of insulation. It has a dense woolly undercoat beneath a layer of coarser guard hairs, and the two do different jobs. The undercoat insulates in both directions — it slows heat coming in as much as heat going out. The guard hairs shed water and, critically, block ultraviolet radiation from reaching the skin.
Shave that off and you remove the sun barrier while leaving the dog with skin that has never been exposed. Sunburn becomes a real risk, and the coat frequently grows back patchy or with a changed texture, sometimes permanently. Huskies, German Shepherds, Golden Retrievers, Australian Shepherds, and Corgis all fall into this category.
De-shedding is what actually cools them
What genuinely helps is removing the dead undercoat rather than the whole coat. Loose undercoat traps heat and blocks airflow at skin level; clearing it out lets air circulate properly, which is exactly the mechanism the coat is designed around.
A thorough de-shedding — a warm bath, a full blow-out to lift the loose hair, and a complete undercoat rake — can pull an astonishing volume of hair out of a double-coated dog. The dog is measurably more comfortable afterward, the coat still protects them from the sun, and as a side benefit your home stops accumulating drifts of fur.
Which coats can be trimmed shorter
Single-coated breeds are a different situation. Poodles, Doodles, Bichons, Shih Tzus, Maltese, and similar continuously growing coats can safely be taken shorter for summer, and often should be. They have no undercoat to protect and no seasonal shed cycle.
Even then, we would not recommend going right down to the skin. Leaving a short but real length gives some sun protection while still being cooler and much easier to maintain through the hot months.
Do not overlook the paws
Bay Area pavement in July can reach temperatures that will burn pads within a minute. The reliable test is to press the back of your hand to the ground and hold it for seven seconds — if you cannot, your dog should not be walking on it. Move walks to early morning or after sunset.
Trimming the fur between the pads helps too. Long pad fur mats readily, collects foxtails, and traps heat, and foxtails are a serious seasonal hazard across the South Bay. We tidy pad fur as part of every full groom.