XS ski gloves are made for hand circumferences of 6 to 6.5 inches, measured around the widest part of your palm (excluding your thumb). This size is most common for youth riders, adults with smaller hands, and some women. To measure, wrap a flexible tape around your palm just below the knuckles and note the number.
Getting the right fit matters a lot for smaller hands. If gloves are too loose, you lose warmth because insulation can't trap heat effectively. But if they're too tight, you'll restrict blood flow — and that's actually the fastest way to end up with freezing fingers on the mountain.
If you're between sizes, it's usually better to size up slightly. And if you plan to wear a liner glove underneath, always try on your ski gloves with the liner in place so you don't end up with a pair that's too snug.