Quick answer: A snowsuit temperature rating, such as -30°C, is the manufacturer's own estimate of the coldest weather that specific garment is built for. It is not a promise that every child will feel warm at that temperature. Read it alongside wind chill, the waterproof rating in mm, breathability in g/m²/24h, seam sealing, fit and your child's activity level.
This guide decodes each number you'll see on a snow suit product page and compares real styles side by side. For brand-by-brand differences, see our guide to kids snowsuit brands in Canada.
Which Snowsuit Specs Matter, and What Does Each One Tell You?
Each spec answers one narrow question, and none of them alone tells you how warm a child will feel.
| Spec on the label | What it tells you | What it doesn't tell you |
|---|---|---|
| Temperature rating (e.g. -30°C) | The coldest conditions the brand designed that garment for | How a specific child feels in wind, when wet, or after an hour outside; exposed skin isn't covered |
| Waterproof rating (mm) | How much water pressure the coated fabric resisted in testing | Whether seams, zippers and cuffs keep water out; results can differ between labs |
| Breathability (g/m²/24h) | How much moisture vapor the fabric let through in the brand's chosen test | How it compares with another brand's number, because tests aren't standardized |
| Seam sealing (fully or critically sealed) | Whether needle holes in seams are covered with tape | Anything about seams the page doesn't mention; don't assume they're sealed |
| Insulation grams (hood, body, limbs) | How much fill sits in each zone of that suit | Warmth on its own; grams of one fill type don't translate directly to another |
What Does a Snowsuit Temperature Rating Actually Mean?
A snowsuit temperature rating is a brand's statement about the coldest conditions a garment is designed for. Deux par Deux, for example, says its DISCOVER, PLAY and TEKNIK snowsuits are insulated down to -30°C (-22°F) and its CHILL line is "designed to cope with temperatures down to -5°C," according to the Deux par Deux snowsuits page. Blizz lists -40°C on the hang tag of its five-piece Beautyberry set, and Nano lists -30°C for its Chris two-piece.
None of the product pages we checked explain which test produced the temperature figure, how long a child was outside, or how active they were. That's why a rating is most useful for comparing suits within one brand's lineup, not as a forecast of comfort.
What doesn't a -30°C rating cover?
A -30°C rating describes the suit, not the child or the weather around them. It doesn't account for:
- Exposed skin. The Canadian Paediatric Society (CPS) lists cheeks, ears, nose, fingers and toes as the body parts most commonly frostbitten.
- Wind. Wind speeds up heat loss from skin and fabric, which is why Canada reports wind chill separately from air temperature.
- Moisture. Sweat from the inside or snowmelt from the outside makes any outfit colder.
- Time and activity. Twenty minutes of sledding and twenty minutes at a bus stop are very different.
- Age. The CPS says babies and toddlers are more at risk of frostbite because they don't move as much and can't tell us when they are cold.
Does a lower temperature rating always mean a warmer snowsuit?
Not necessarily. Brands may rate their suits differently, so a 10-degree gap on paper isn't proof that one suit is warmer. Compare fill type and grams, lining, how well the cuffs and snow skirt seal, and whether the shell stays dry.
How Does Wind Chill Change a Snowsuit Temperature Rating?
Wind chill doesn't change the rating on the tag, but it changes the conditions your child is in. Environment and Climate Change Canada explains on its Wind chill and the Wind Chill Index page that "the weather outside feels colder when it is windy," and that the index is used "to help describe the risk of frostbite." The same page notes that wind chill "doesn't make things colder than the real air temperature," but it does speed up heat loss.
Here's the Government of Canada's risk scale for wind chill exposure:
| Wind chill | Risk | What the Government of Canada says |
|---|---|---|
| 0 to -9 | Low | Slight increase in physical discomfort |
| -10 to -27 | Moderate | Hypothermia and frostbite are a risk if outdoors for long periods without adequate protection |
| -28 to -39 | High | Exposed skin can freeze in 10 to 30 minutes |
| -40 to -47 | Very high | Exposed skin can freeze in 5 to 10 minutes |
| -48 to -54 | Severe | Exposed skin can freeze in 2 to 5 minutes |
| -55 or colder | Extreme | Exposed skin can freeze in less than 2 minutes; outdoor conditions are hazardous |
The page adds that in sustained winds over 50 km/h, frostbite can occur faster than indicated.
What outdoor temperature limits do pediatric groups give?
Pediatric groups set limits well above -30°C. The CPS, in its Frostbite handout, suggests considering keeping children indoors "whenever the temperature or the wind chill is reported to be -27°C (-16°F) or lower," because exposed skin begins to freeze at that point. It also advises planning less outdoor time when it is -15°C (5°F) or colder, with or without wind chill. The American Academy of Pediatrics (AAP) says that, in general, playing outside in temperatures or wind chills below -15°F (about -26°C) should be avoided.
A -30°C snowsuit gives you more margin on a -20°C morning. It doesn't make a -30°C wind chill a good day for long outdoor play.
What Does a Waterproof Rating in mm Mean?
A waterproof rating in millimetres (mm) tells you how tall a column of water the fabric held back in a lab test before leaking. The outdoor retailer evo explains in its guide How Waterproof & Breathability Ratings Work that most tests involve "the equivalent of placing a 1" x 1" square tube over the fabric and determining how high (in millimeters) a column of water you can suspend over it before it starts to leak." Outdoor brand Kathmandu, in What do waterproof and breathability ratings actually mean?, calls this hydrostatic head, or "HH," and describes it as "an industry-standard waterproof rating." In its example, 10,000 mm means 10 metres of water sat on the fabric without leaking.
The higher the number, the more water pressure the fabric resisted. evo cautions that "different labs may test or report differently," so treat the figure as a guide.
What do the waterproof rating bands mean?
Rating bands vary by brand and retailer. This table summarizes evo's waterproof chart:
| Waterproof rating | Water resistance (evo) | Conditions (evo) |
|---|---|---|
| 0–5,000 mm | No resistance to some resistance to moisture | Very light rain, dry snow, no pressure |
| 6,000–10,000 mm | Rainproof and waterproof under light pressure | Light rain, average snow, light pressure |
| 11,000–15,000 mm | Rainproof and waterproof except under high pressure | Moderate rain, average snow, light pressure |
| 16,000–20,000 mm | Rainproof and waterproof under high pressure | Moderate rain, wet snow, some pressure |
| 20,000 mm+ | Rainproof and waterproof under very high pressure | Heavy rain, wet snow, high pressure |
"Pressure" is the key word for kids. evo notes that wind, sitting and falling all push water against the fabric, and children kneel, sit on snowbanks and slide far more than adults do.
Is 10,000 mm waterproof enough for kids?
For most everyday snow play, 10,000 mm falls in evo's band for "light rain, average snow, light pressure." For wet spring snow, slush or long days of sitting and kneeling, a higher figure gives more margin. evo recommends a minimum of 5,000 mm for snow pants and ski or snowboard jackets, and 10,000 to 20,000 mm for avid skiers in wetter climates. If your winters bring more slush than powder, our rain suit vs snowsuit guide covers the in-between days.
Does "water repellent" mean the same as waterproof?
No. A durable water repellent (DWR) is a surface treatment. evo explains that DWR "causes water to bead-up and roll off the fabric" and that abrasion, dirt and body oils wear it down. When a page says "water repellency" or "impermeability," read the wording and the number together. Our snowsuit care guide covers washing outerwear.
What Does Breathability in g/m²/24h Mean?
Breathability is how well a fabric lets sweat vapor escape from the inside, usually listed in grams per square metre over 24 hours (g/m²/24h). Kathmandu describes it as the Moisture Vapor Transmission Rate (MVTR): "the amount of moisture that can pass through a square metre of fabric over the course of 24 hours." A higher number generally means more vapor gets out. Breathability matters for children because, as the CPS puts it in its winter advice for parents, a child dressed too warm "could sweat and feel colder when they stop playing."
Treat breathability numbers with more caution than waterproof numbers. evo says breathability testing methods "are quite diverse and almost impossible to compare with each other," are "not standardized from brand to brand, or test to test," and that within a given brand or family of fabrics, more grams is generally more breathable.
| Breathability | Who evo suggests it suits |
|---|---|
| 5,000–8,000 g | Lift-served riding with regular indoor breaks; more casual uses |
| 10,000–15,000 g | "High energy" activity where you often break a sweat |
| 20,000 g+ | Backcountry skiers and snowboarders, runners, mountain bikers |
Why do some product pages list breathability in mm?
Sometimes a page lists breathability in mm, the unit for waterproofing. The Nano Chris two-piece snowsuit page, for example, lists "5000 mm water repellency, 5000 mm breathability." Don't compare that figure with a g/m²/24h number; check the product page or ask us what was measured.
What Is the Difference Between Fully Sealed and Critically Sealed Seams?
Seam sealing covers the tiny holes a sewing needle leaves behind. evo explains that a fully taped garment "has every seam taped," while a critically taped one "has tape only on high exposure areas," and warns that "without adequate seam sealing you'll get wet even with the best waterproof/breathable fabric."
Deux par Deux, for example, lists "fully sealed seams" on its CHILL line and "critically sealed seams: at armholes, shoulders, hood, and crotch" on TEKNIK. If a page doesn't mention seams, don't assume they're sealed.
What Do Insulation Grams Tell You?
Insulation grams tell you how much fill is in each zone of a suit. Deux par Deux is one of the few brands that lists them. Its snowsuits page lists PLAY and DISCOVER fill as 57 g in the hood and 170 g in the body, sleeves and legs, and TEKNIK's PrimaLoft® insulation as 100 g in the hood, 170 g in the body and 133 g in the sleeves and legs.
Compare grams only between suits with the same type of fill. PrimaLoft® and standard polyester fill are different materials, so fewer grams of one isn't automatically less warm than more grams of the other.
How Do Activity, Sweat and Wet Clothes Change Warmth?
Activity is the biggest variable a rating can't predict. The CPS notes that "if your child's feet and hands are warm, what they are wearing is usually good," and that active games help keep children warm. The flip side is sweat.
The AAP, in Playing Outside in Winter, explains that children lose heat more quickly than adults because their bodies are smaller, and that kids having fun may be less likely to come inside when they're getting too cold. It recommends several thin layers, regular indoor breaks and changing out of wet clothes right away. The CPS adds mittens instead of gloves, a hat that covers the ears, and a neck warmer instead of a scarf.
Start with a thin layer from kids base layers. For a full layering plan, see what to wear under a snowsuit, and for mitts, toques and neck warmers, browse winter accessories.
How Do You Compare Two Snowsuits Step by Step?
Line up the same specs from each product page, in the same order, and note where a page is silent or unclear:
- Match the format first. Compare a one-piece with a one-piece, or a two-piece with a two-piece. If you haven't decided, read our one-piece vs two-piece snowsuit guide.
- Note who set the temperature rating (brand page, hang tag).
- Record the waterproof rating and its wording. "Waterproof," "coating" and "water repellency" aren't interchangeable.
- Record breathability and its unit. Only compare g/m²/24h with g/m²/24h.
- Check seams. Fully sealed, critically sealed, or not mentioned.
- Compare insulation type and grams within the same fill type.
- Check the snow-blocking details. Snow skirt or powder skirt, ankle gaiters, cuffs and hood snow guards.
- Check fit advice and current sizes using our snowsuit sizing guide.
- Match it to your child's real day: recess, daycare walks or ski lessons.
Worked example: PLAY vs TEKNIK vs Blizz
Here's that process applied to three jacket-and-snow-pants styles carried at Jenni Kidz: two from our two-piece snowsuits collection and one Blizz set that also includes a hat, neck warmer and mitts or gloves. Every figure is quoted from the live Jenni Kidz product page as of November 2026.
| Spec | Deux par Deux PLAY Two-Piece, Red With Black Pants | Deux par Deux TEKNIK Two-Piece, Royal Blue And Yellow | Blizz Girls Snowsuit 5-Piece Set, Beautyberry |
|---|---|---|---|
| Temperature rating | -30°C (-22°F), by Deux par Deux | Hood rated to -30°C (-22°F) | -40°C (Blizz hang tag) |
| Waterproof | 10,000 mm polyurethane coating | 15,000 mm waterproof | 5,000 mm impermeability (Blizz) |
| Breathability | 5,000 g/m²/24h | Check the product page (see note below) | Not listed |
| Seams | Not listed on this page | Not listed on this page | Not listed on this page |
| Insulation | Polyester fill: 57 g hood, 170 g body, 170 g sleeves and legs | PrimaLoft®: 100 g hood, 170 g body, 133 g sleeves and legs | 100% polyester polyfill (grams not listed) |
| Snow-blocking details | Snow skirt, ankle snow gaiters, hood snow guard | Adjustable powder skirt | Faux-fur trimmed hood; reinforced inside hem |
| Sizes listed | 2–14 | 4–16 | 4Y–16Y |
What the table tells you. The Blizz set has the coldest temperature rating but the lowest waterproof figure, so it lines up with cold, dry days more than slushy ones. The PLAY set sits in evo's 6,000–10,000 mm band, which fits everyday snow play and recess. The TEKNIK set has the highest waterproof figure, which adds margin for wet snow, kneeling and long days on the hill. Deux par Deux describes TEKNIK as built for winter sports.
Where the pages disagree. The TEKNIK product pages list breathability as 15,000 g/m²/24h, while the Deux par Deux snowsuits page lists 5,000 g/m²/24h for TEKNIK. Until those match, check the product page or ask us before you rely on either number. The brand page also lists TEKNIK's seams as critically sealed, even though the product page doesn't mention seams.
Prefer a one-piece? The same comparison works for the PLAY One-Piece Snowsuit, Multicolored Line Print (sizes 2–14; 10,000 mm, 5,000 g/m²/24h, rated to -30°C by Deux par Deux) and the TEKNIK One-Piece Snowsuit, Bright Orange And Blue (sizes 4–16; 15,000 mm; critically seam-sealed at the armholes, shoulders, hood and crotch). Browse more in one-piece snowsuits. For a deeper line-by-line look at the Deux par Deux range, read Deux par Deux DISCOVER vs PLAY vs TEKNIK.
What Are the Signs a Child Is Too Cold?
Watch your child, not the label. The CPS describes how frostbite progresses. Skin first turns red and swollen and stings or burns. If it isn't warmed, it tingles and looks grey. If it freezes, the area loses feeling and looks shiny and white. The CPS also describes frostnip, a milder form that leaves skin red and numb or tingly and gets better with rewarming.
The AAP describes hypothermia as a drop in body temperature below normal. A child may start shivering, then become "sluggish, clumsy or slur their words." The AAP calls hypothermia a medical emergency and says to call 911.
- Check often. The CPS recommends checking that your child is warm and dry and giving younger children indoor breaks.
- Rewarm gently. The CPS advises warm (not hot) water and no rubbing, and to seek medical advice right away if skin is white, waxy or numb.
This section is general information about cold-weather health, not medical advice. If you're worried about frostbite or hypothermia, contact a health professional or call 911 in an emergency.
Should Kids Wear a Snowsuit Under a Car Seat Harness?
No. The AAP's winter car seat tips say that, as a general rule, "bulky clothing, including winter coats and snowsuits, should not be worn underneath the harness of a car seat," because padding can flatten in a crash and leave the straps loose. The AAP suggests thin layers, a snug harness, and a coat or blanket placed over the buckled straps. Transport Canada's winter driving page also says bulky winter coats and snowsuits may not work well with a child's car seat and to follow your car seat manual. A temperature rating says nothing about car seat use. Our winter car seat and snowsuit guide walks through the routine step by step.
What Should You Check Before You Buy a Snowsuit?
Run through this checklist with the product page open:
- Who set the temperature rating, and does it match your coldest typical day once wind chill is factored in?
- Is the waterproof rating in mm, and does the wording say waterproof, coating or water repellent?
- Is breathability listed in g/m²/24h, and is it consistent with the brand's own page?
- Are the seams fully sealed, critically sealed or not mentioned?
- Is the size based on today's measurements, with room only for the layers you'll actually use?
Then shop our kids snowsuits collection, compare lines in Deux par Deux, or see the full sets in Blizz. For recess, see our preschool and elementary snowsuit guide and winter coat or snowsuit for school. For babies, start with the baby snowsuit buying guide.
Frequently Asked Questions About Snowsuit Temperature Ratings
What does a -30°C rating on a snowsuit mean?
It is the manufacturer's estimate of the coldest conditions that specific snowsuit is designed for. It doesn't cover exposed skin, wind chill, wet clothing or how long a child stays outside, so treat it as a comparison point, not a comfort guarantee.
Is a -40°C snowsuit warmer than a -30°C snowsuit?
Not automatically. The product pages we checked don't explain the test behind their temperature ratings, so a 10-degree gap between two brands isn't proof of extra warmth. Compare insulation type and grams, seals at cuffs and waist, and the waterproof rating too.
What waterproof rating should a kids snowsuit have?
The retailer evo recommends at least 5,000 mm for snow pants and ski or snowboard jackets. In its chart, 6,000–10,000 mm covers light rain and average snow under light pressure. Kids who sit, kneel and slide in wet snow benefit from a higher figure.
What does 5,000 g/m²/24h breathability mean?
It means the fabric let about 5,000 grams of moisture vapor pass through a square metre in 24 hours in the brand's test. Breathability tests aren't standardized, so compare figures within one brand rather than across brands.
Does wind chill matter if a snowsuit is rated -30°C?
Yes. A snowsuit rating doesn't cover exposed skin. Environment and Climate Change Canada says exposed skin can freeze in 10 to 30 minutes at a wind chill of -28 to -39, and the Canadian Paediatric Society suggests considering keeping children indoors at -27°C (-16°F) or lower, temperature or wind chill.
Do sealed seams matter on a snowsuit?
Yes, in wet conditions. evo explains that without adequate seam sealing you can get wet even in waterproof fabric. Critically sealed means only high-exposure seams are taped; fully sealed means every seam is.
Sources
- Environment and Climate Change Canada, Canada.ca: Wind chill and the Wind Chill Index
- Canadian Paediatric Society, Caring for Kids: Frostbite (last updated February 2023)
- Canadian Paediatric Society, Caring for Kids: Winter safety: Advice for parents and kids
- American Academy of Pediatrics, HealthyChildren.org: Playing Outside in Winter: Tips to Keep Kids Warm & Safe
- American Academy of Pediatrics, HealthyChildren.org: Winter Car Seat Safety Tips: Keeping Kids Safe & Warm
- Transport Canada: Driving safely in winter
- evo: How Waterproof & Breathability Ratings Work
- Deux par Deux: Snowsuits (product line technical specifications)
- Kathmandu: What do waterproof and breathability ratings actually mean?
Product details come from the live Jenni Kidz product pages and the Deux par Deux website as of November 2026. Specs can change between seasons, so always confirm on the product page before you buy. This article is general information, not medical advice.
