Fabric weight guide
Which merino weight is right for you?
GSM is grams per square metre — how much fabric there is, not a warmth rating. Every weight is the same soft 17.5-micron Australian merino: it wicks sweat before it turns cold, insulates when it is cold and ventilates when it is warm. Lighter fabric breathes and dries faster; heavier fabric holds more heat when you stop moving. Choose by season and by how hard you will be working.
Warm & hot weather · 60°F+ / 15°C+ — and high effort in any season
Best for: summer hiking, running, cycling, hot-climate travel, everyday tees and office wear; the next-to-skin layer under a 250 when you work hard in winter
Pick this if: you want a shirt that stays fresh for days, dries in an hour and keeps you cooler than cotton in the heat — or you simply run hot
Think twice if: you will mostly be standing still in the cold; on its own a lightweight layer has little insulation to offer
Shop 165 GSM →Cool to mild · 40–65°F / 5–18°C
Best for: spring and autumn as a standalone top, summer evenings, cool-morning hikes and commutes; winter as a base under a mid-layer
Pick this if: you want one merino layer that covers most of the year, or you are unsure between light and mid — this is where most people should start
Think twice if: you run cold and your winter is genuinely cold: go straight to 250
Shop 190 GSM →Cold · 20–45°F / −7–7°C — the classic winter base layer
Best for: skiing and snowboarding, winter hiking, cold-weather work, frosty autumn mornings; top-and-bottom sets so your legs are not the weak link
Pick this if: you run cold in fall, want the classic winter base layer, or spend active days below freezing under a shell
Think twice if: you overheat easily on hard uphill efforts — a 165 or 190 underneath, 250 over it, is the better system
Shop 250 GSM →Deep cold · below 25°F / −4°C — especially when you stop moving
Best for: ice fishing, hunting stands, camp at altitude, winter mornings spent waiting rather than walking, a house that never quite gets warm
Pick this if: warmth matters more than breathability, you are chronically cold, or your winter involves long spells standing still outdoors
Think twice if: you will be working hard — it is too warm for a sweaty climb, which is exactly the point
Shop 320 GSM →A base layer works by sitting close to the skin, where it can move moisture — loose is not more comfortable, just slower. Between sizes? Size down for a next-to-skin layer under a shell, size up to wear it on its own or over another layer. Merino stretches with wear and springs back after a wash. Heavier weight is not itchier: itch comes from coarse fibre, and every weight here is the same superfine merino.
Size guide
Size Guide
Our merino has a close, next-to-skin fit by design. If you are between sizes, stay true to size for base-layer use or size up for a more relaxed everyday fit. Free returns within 30 days, so ordering two sizes and sending one back is completely fine.
How to measure
Chest — around the fullest part of your chest, with the tape level under the arms.
Waist — around your natural waistline, with the tape comfortably loose.
Hips — around the fullest part of your hips and seat.
Inside leg — from the top of your inner thigh to your ankle bone.
Measure over light clothing, keeping the tape snug but not tight. Tap any chart below to open it full size.
Men's Base Layer Set
Need different sizes for the top and the bottoms? Build your own set →
Women's Base Layer Set
Need different sizes for the top and the bottoms? Build your own set →
Kids' Base Layer Set
Men's T-Shirt
Women's T-Shirt
Men's Long Sleeve
Same body measurements across 165, 190, 250 and 320gsm.
Women's Long Sleeve
Kids' Long Sleeve
Men's Long Johns
Women's Thermal Leggings
Kids' Thermal Leggings
Men's Half Zip
Women's Half Zip
Merino Wool Socks
Beanies, snoods and balaclavas
Still unsure which size to pick? Email info@merinotech.co.uk with your height, chest and waist and we will recommend a size. Free UK delivery over £49 and free returns within 30 days.
- Free shipping over $49.99
- 30-day easy returns
- Ships in 1–2 business days
Description
Women's Merino Pants
Whether you’re training indoors or exploring outdoors, our Women’s Merino Pants are built to perform. Merino wool’s thermoregulating structure keeps you cool during workouts and warm afterward, while its moisture-wicking power ensures you stay dry.
The natural antibacterial properties prevent odour buildup, so you can wear them multiple times between washes. Lightweight, breathable, and soft to the touch, these pants transition effortlessly from gym to trail to travel — keeping you comfortable every step of the way.
Care
Turn inside out. Machine wash cold on a gentle cycle with a wool-safe detergent. Do not bleach. Lay flat or hang to dry.
Shipping & returns
Free UK delivery on orders over £49. Ships in 1–2 business days. 30-day free returns on unworn items with tags.
Women's base layer pants
The bottom half of staying warm
A soft merino legging with a wide comfort waistband and flatlock seams. Wear under ski pants, jeans or hiking trousers — or on their own at home.
Size guide
Women's Pants 165
Fit
A close, next-to-skin fit made to sit smoothly under trousers, jeans and salopettes. Between sizes? Go by your waist measurement.
How to measure
- Chest – around the fullest part of your chest, tape level under the arms.
- Waist – around your natural waistline, tape comfortably loose.
- Hips – around the fullest part of your hips and seat.
- Inside leg – from the top of your inner thigh to your ankle bone.
Measure over light clothing and keep the tape snug but not tight. Still unsure? Email info@merinotech.co.uk with your height, chest and waist and we will recommend a size. Unworn items can be returned free within 30 days.
THE FABRIC
Why merino wool
Merino wool moves sweat away from your skin as vapour and lets it evaporate from the fabric, so you stay dry and comfortable whether you are hiking, commuting or skiing.
Merino fibres naturally resist the bacteria that cause odour, so you can wear a base layer for several days, on the trail or while travelling, and it still smells fresh.
Wool can absorb up to 30% of its weight in moisture without feeling wet. In damp British weather it keeps insulating where cotton and polyester leave you cold.
Merino absorbs UV radiation: our lightweight layers offer UPF 25 and the midweight and heavyweight options UPF 50+, handy on long days in the hills.
Merino wool is naturally hard to ignite and self-extinguishes without melting onto the skin, unlike synthetic base layers.
Merino is a natural, renewable and biodegradable fibre. Sheep grow a new fleece every year, and a worn-out merino garment breaks down instead of shedding plastic microfibres.
FAQ
Women's merino thermal leggings: FAQ
What is this 165gsm thermal leggings best for?
It is a lightweight 165gsm merino layer, best for running, cycling, travel and layering. Compare every weight in our merino weight guide.
Is this thermal leggings warm enough for skiing?
It works for spring skiing, ski touring or as a thin layer under a warmer mid layer. For a standard winter ski week, most people choose 250gsm.
What are merino thermal leggings used for?
They are a base layer worn under trousers, ski salopettes or waterproofs to keep your legs warm and dry. Merino regulates temperature, so they stay comfortable when you move indoors or start working hard.
Which weight of merino leggings should I choose?
165gsm for mild days and active sports, 200gsm for cool everyday wear and layering, 250gsm midweight for most winter activities and skiing, and 320gsm heavyweight for very cold conditions.
Can I wear merino leggings under jeans or a skirt?
Yes. The fabric is smooth and the seams lie flat, so the leggings sit neatly under jeans, work trousers, dresses and skirts on cold days.
How should women's merino leggings fit?
Close-fitting without restricting movement, with a comfortable waistband. They are true to size; compare your waist and hip measurements with the size guide.
How do I wash merino leggings?
Inside out at 30°C or lower on a wool cycle with a wool-safe detergent, then dry flat or hanging. No tumble dryer and no fabric softener.