A Medium ski glove typically fits a hand circumference of 7.5 to 8.5 inches measured around the widest part of your palm (excluding the thumb). This size works well for average men and larger women. To check your size, wrap a soft tape measure around your dominant hand at the knuckles and compare it to the brand's size chart — sizing can vary between manufacturers.
Getting the fit right matters more than you'd think. If your gloves are too tight, they restrict blood circulation, which actually makes your hands colder even with premium insulation. If they're too loose, you lose warmth because there's too much air space to heat and the insulation can't trap body heat effectively. You want a snug fit with a small air gap at the fingertips — that gap is where insulation works best.
Always try on gloves with any liner you plan to wear underneath. If you're between sizes, it's usually smarter to size up slightly rather than squeeze into a tighter glove.