Small dog, small margins
A Yorkshire Terrier's heat sensitivity is a matter of scale. A dog who may weigh less than a bag of sugar has very little body mass to buffer temperature changes, only small amounts of water and energy in reserve, and short legs that place her whole body close to ground radiating the day's stored heat. She can become uncomfortable on a summer pavement walk while the person holding the lead, a long way above the asphalt, still feels fine. Her coat cuts both ways: the fine, silky, single coat — more like human hair than a double coat — traps far less heat than a Husky's or Sheltie's, which is a genuine benefit, but it also offers her skin little protection from direct sun during long periods outdoors.
Coat, skin and grooming in hot weather
Many owners keep a Yorkie in a shorter puppy clip for summer, and for a pet dog that is a sensible, comfortable choice: it reduces tangling from harness wear and damp grass, makes it easy to wet her through if she gets hot, and lets you see her skin. If her coat is long, part it and check the skin on her back during sunny spells, because fine hair is a poor sunshade over a whole afternoon in the garden. Brush her gently and often — a small dog's coat mats quickly behind the ears and under a harness, and mats pull on skin that is already warm and sensitive. After walks, check her tiny paws for heat soreness, seeds, and grit, and rinse them if she has walked anywhere that may have been treated or salted in summer maintenance.
Planning outings at Yorkie scale
Think in minutes and metres rather than miles. Her main walks belong in the morning and evening; a midday outing is a few shaded minutes for a toilet break, ideally on grass. Carry water and a collapsible bowl on anything longer, because a Yorkie will not drink on schedule — offer it at every stop and let her take small amounts often. In a bag or carrier she is closer to your body heat and may have poor airflow, so check her frequently, keep the carrier shaded and ventilated, and never leave her in one in the sun while you sit at a cafe. Cars are an absolute rule for this breed too: a tiny dog in a warming car deteriorates very fast, so she comes with you or stays home in the cool, with no in-between. At home she will manage her own comfort well if you provide options — a cool floor spot, shade in the garden, and water in the room she has chosen.
The Yorkie version of a heat warning
In a dog this small, deterioration can be quick and quiet. Early signs include panting that does not settle, unusual restlessness followed by unusual stillness, refusing treats, drooling, red gums, vomiting, or a wobbly, fragile quality to her movement. Because small toy breeds can also drop their blood sugar when they miss food and over-exert in heat, weakness or trembling on a hot outing should never be brushed off. Move her to shade or a cool room, offer small sips of cool water, dampen her belly, neck and paws, and contact your veterinarian promptly if she does not brighten quickly, seems weak or trembly, vomits repeatedly, or collapses — with a dog of this size, err on the side of calling early, and tell the vet her size and what the outing involved.
Everyone walks her the same careful way
A Yorkie is often walked by several people — children, grandparents, neighbours — each with a different sense of how far is fine. Relatives you select can be granted access via KinsLe's Family Sharing to the profile kept for her, and can open that profile firsthand rather than learn about her from somebody else's account.