Fleece GSM and Layer Counts: What the Numbers Say About Glove Warmth

You've got three product pages open. One glove lists 320 gsm fleece, another a three-layer build, the third a six-layer construction. What you really want to know is which one keeps your fingers comfortable on a 30-minute walk to the train, and none of those numbers tells you directly.

Fleece GSM is the weight of one fabric per square meter. It describes a material, and it isn't a warmth rating. A layer count describes how the glove is put together, and many layers are there to block wind or water rather than to insulate. Both numbers are useful for comparing similar gloves and for working out what to ask. Neither one converts into a temperature, and six layers aren't automatically twice as warm as three.

GSM stands for grams per square meter. Fleece listed at 320 gsm means a one-meter square of that fabric weighs 320 grams. That's not the weight of the glove, which uses only a small piece of the fabric, and it's not the weight of the pair either. It also says nothing about the other materials the fleece is sewn to.

Weight is a fair way to compare two versions of the same kind of fleece, since more fabric per square meter usually means more material to hold air. Across different fabrics, the comparison breaks down. Warmth comes mostly from still air, and how much air a fabric holds depends on its structure as well as its weight. Fabric makers design around exactly that. Polartec, for example, describes its Thermal Pro fleece as using knit structures to trap heat and deliver warmth without weight. We're citing it only to illustrate the design idea; it doesn't describe any glove in this article.

GSM is also measured on flat, dry fabric. Inside a glove, the same fleece can get pressed flat by a tight fit or soaked by sweat or snow. Canada's occupational safety agency, CCOHS, notes that wet inner layers lose insulation dramatically and compressed layers insulate less. So a heavier fleece in a glove that's a size too small can feel colder than a lighter one that fits. Before you go up in fleece weight, check how tight a winter glove should be.

A layer count tells you how many distinct materials sit between your hand and the weather. It doesn't tell you what each one does. In winter gloves, the layers usually split into a few jobs: an outer shell that takes abrasion and sheds light moisture, a membrane or insert that keeps liquid water out, a wind-blocking layer, insulation that holds still air, and a lining against the skin. Only some of those are there mainly for warmth.

Barriers come with trade-offs. SATRA, an independent testing organization, notes that breathable materials reduce moisture build-up but also add to heat loss, and every extra layer changes how quickly sweat can get out. So more layers can make a glove better for wet, still conditions and worse for a hard run. If sweat is your main problem, read why hands get sweaty and then cold in running gloves.

Whole-glove warmth can be measured. EN 511, the European standard for protective gloves against cold, includes a convective cold test that puts the glove on an electrically heated hand in a controlled cold environment and measures the power needed to keep that hand warm. Separate tests cover contact cold, like gripping a cold surface, and water penetration. SATRA's overview makes the point that these are distinct tests with distinct results. Warmth in moving air, warmth against a cold object and keeping water out are three different questions.

Because EN 511 is written for protective gloves, it's normal for an everyday commuting or running glove to have no rating. That just means there's no lab result to compare. It doesn't make the glove unsuitable for daily wear. If a brand does publish whole-glove results, look for the method, the conditions, and whether the tested sample matches the glove on sale. If it doesn't, a clear description of what each layer does will tell you more than a bigger number.

• Moving steadily, like running or a brisk walk: a lighter, close-fitting glove often works better than a heavy stack. Your hands are making heat, and the sweat needs somewhere to go.
• Standing and waiting at a bus stop, a sideline or a dog park: insulation and wind protection count for more. Look at a warmer construction, or mittens or a split-finger design if you rarely need your fingers.
• Wet days: look for a waterproof layer and check how the cuff meets your sleeve. Once the lining is soaked, no fleece weight helps, so the difference between waterproof and water-resistant gloves matters more.
• Comparing two gloves: only compare GSM between similar fabrics in similar constructions. Between a knit liner and an insulated shell glove, it tells you very little.
• Trying them on: make a fist and curl your fingers. If the lining presses flat across the knuckles or the fingertips feel tight, you're losing loft. Check the glove sizing guide before going up in weight.
• Reading a temperature range: treat it as brand use guidance, then adjust for wind, wet, effort, time outside and your own circulation. Running gloves by temperature shows how that works.

Our own specs work the same way. The Aerynx X1 Lite lists 320 gsm fleece, and that figure describes its fleece interior. It's a light, four-way-stretch glove for active wear. It's water-repellent, not waterproof, and we give 41–59°F (5–15°C) as brand use guidance for wearing it on its own. That range isn't a safety rating, and wind, wet and effort will move it.

The 2026 Aerynx X2 Daily is a three-layer build: a waterproof soft-touch shell, a wind-blocking mid-layer and a graphene-fiber fleece lining. Here the count maps to three jobs: wet weather, wind and insulation. Our explainer on how graphene gloves work covers what that lining is and isn't. X2 is built for wet-weather wear, not soaking or submersion, and water can still find a way in at seams and the cuff. Its 32–50°F (0–10°C) solo-wear figure is brand use guidance.

The Aerynx X3 Winter has six layers: a nylon shell, a membrane, synthetic insulation, a separate waterproof insert, inner insulation and short-pile fleece. Two of those, the membrane and the insert, are there to keep water out. The fleece lining is fixed in place, so give it time to dry between outings. We don't publish a temperature rating for X3, and we won't turn its layer count into one. It isn't built for soaking either; seams can still let water in. Think of the six layers as a heavier-duty build for still, cold or wet days. They aren't a multiple of X2's warmth. If you're weighing the three against each other, the winter glove buying checklist starts from the jobs you need a glove to do.