It’s 2 AM. You tiptoe into the nursery to check on your little one. You touch their hand—it feels like an ice cube. Panic sets in. You reach for a blanket, but then you touch their back and realize they are actually warm.
Does this scenario sound familiar?
For new parents, the fear of a baby being too hot or too cold is a nightly struggle. We know that overheating is a significant risk factor for SIDS (Sudden Infant Death Syndrome), but the fear of a baby waking up shivering is just as real.
Stop guessing. There is a science to keeping your baby comfortable, and it starts with three letters: TOG.
Understanding TOG ratings is essential when choosing the right baby sleep sacks (wearable blankets) to ensure safe thermal regulation. Instead of relying on guesswork, this guide will help you decode the numbers so you can dress your baby with confidence, no matter the season.
What Does TOG Stand For? (The Basics)
TOG stands for "Thermal Overall Grade," a standard unit of measurement used to calculate the thermal insulation of a textile product, usually in bedding or sleepwear. Put simply: the higher the TOG rating, the warmer the sleep sack. This rating system helps parents dress their babies appropriately for the specific room temperature without the safety risks associated with using loose blankets.
While you might just throw on an extra duvet when you're cold, dressing an infant is more complex. Babies, especially newborns, cannot regulate their body temperature as efficiently as adults. They lose heat nearly four times faster than you do, yet they can also overheat quickly if overdressed.
A TOG rating acts as your safety gauge. It tells you exactly how much heat a sleep sack or swaddle retains. By matching the TOG to your nursery's temperature, you create a neutral thermal environment where your baby can sleep safely—not too hot, not too cold, but just right.
The Baby Sleep TOG Chart: How to Dress Your Baby
To ensure safe sleep, match the TOG rating to your nursery's temperature. Use 0.5 TOG for warm rooms (75-80°F), 1.0 TOG for standard conditions (69-73°F), and 2.5 TOG for cooler environments (61-68°F). Always adjust the layers of clothing underneath—such as bodysuits or footie pajamas—based on your baby’s comfort level.
Think of TOG ratings as a roadmap. Once you know the temperature of your nursery, the rating tells you exactly which "route" to take. However, a sleep sack is just the outer layer. The secret to perfect thermal regulation lies in what you put underneath.
Understanding the number is step one. To see exact outfit combinations for each rating, check our practical guide on how to dress baby for sleep.
Here is the breakdown of the three most common TOG ratings and how to layer them effectively:
0.5 TOG: The Summer Essential (75°F - 80°F / 24°C - 27°C)
This lightweight option is designed for hot summer nights, daytime naps in warmer rooms, or homes without strong air conditioning. 0.5 TOG is essentially a single sheet layer.
What to wear underneath:
- 78°F+ (26°C+): Short-sleeve bodysuit (onesie) or just a diaper.
- 75°F - 77°F (24°C - 25°C): Short-sleeve bodysuit.
1.0 TOG: The Year-Round Standard (69°F - 73°F / 21°C - 23°C)
If you only buy one sleep sack, make it a 1.0 TOG. This is the "Goldilocks" rating—not too thick, not too thin. It is perfect for most modern homes that keep the thermostat steady around 70-72°F.
What to wear underneath:
- 71°F - 73°F (22°C - 23°C): Short-sleeve bodysuit.
- 69°F - 71°F (20°C - 21°C): Long-sleeve bodysuit or light footless pajamas.
2.5 TOG: The Winter Warmer (61°F - 68°F / 16°C - 20°C)
This padded rating is built for drafty houses or cold winter nights. 2.5 TOG functions like a duvet comforter for your baby.
What to wear underneath:
- 64°F - 68°F (18°C - 20°C): Long-sleeve footie pajamas.
- 61°F - 63°F (16°C - 17°C): Long-sleeve bodysuit plus footie pajamas (double layer if necessary, but proceed with caution).
Pro Tip: These temperatures refer to the room where the baby sleeps, not the thermostat setting in your hallway. We recommend keeping a simple room thermometer near the crib (but out of reach) for the most accurate reading.
Warning Signs: Is My Baby Too Hot or Too Cold?
To accurately determine your baby's temperature, place the back of your hand on their chest or the back of their neck. If this area feels hot or sweaty, your baby is overheating, and you should remove a layer immediately. If it feels cool, add a layer. Do not judge based on their hands or feet, which are naturally cooler.
It is the most common panic moment for new parents: You touch your sleeping baby’s hand, and it feels freezing cold. Your instinct screams at you to add a heavy blanket.
Stop. Do not add that blanket.
The "Cold Hands" Myth
Newborns have immature circulatory systems. Their bodies prioritize keeping vital organs (heart, lungs) warm, meaning blood flow is often shunted away from extremities like hands and feet.
- Fact: Cold hands and feet are completely normal for young infants.
- Fact: If your baby’s hands are cold but their chest is warm and dry, they are perfectly comfortable.
The "Touch Test" (How to Check Properly)
Forget the forehead; forget the hands. The only accurate way to gauge your baby’s core temperature without a thermometer is the Torso Touch Test.
- Gently slip your hand down the back of the sleep sack or place two fingers on their chest.
- Hot/Sweaty: Your baby is overdressed. This is a safety risk. Lower the room temperature or switch to a lower TOG rating.
- Cool: Your baby might be slightly underdressed. Consider switching from a short-sleeve to a long-sleeve bodysuit underneath.
- Warm/Dry: This is the sweet spot. No action needed.
Critical Signs of Overheating
While being a little cold might make a baby fussy, being too hot is dangerous. Overheating is a known risk factor for SIDS. Watch for these red flags, which often indicate you are using a TOG rating that is too high for the room:
- Damp hair or a sweaty neck.
- Flushed, red cheeks.
- Heat rash (prickly heat) on the chest or back.
- Rapid breathing.
Creating a safe sleep environment is about balance. By following safe sleep guidelines and using the correct TOG rating, you reduce these risks significantly.
Why Fabric Material Matters as Much as TOG
While a TOG rating measures how much heat a garment holds, the fabric material determines how breathable it is. Synthetic fabrics like polyester fleece often trap moisture and heat, leading to the "cold sweat" effect. In contrast, breathable fibers like Viscose from Bamboo allow excess heat to escape, regulating body temperature more effectively at the same TOG rating.
You might assume that a 1.0 TOG polyester sack and a 1.0 TOG bamboo sack provide the exact same warmth. Technically, they have the same thermal resistance. However, the experience for your baby is vastly different.
The "Plastic Bag" Effect (Polyester & Fleece)
Many budget-friendly sleep sacks are made from polyester or microfiber. While durable, these synthetic fibers are essentially plastic. They trap body heat effectively but do not allow moisture to evaporate.
- Result: Your baby might wake up with damp hair or clammy skin because their sweat had nowhere to go.
The "Thermostat" Effect (Viscose from Bamboo)
This is why many parents are switching to Viscose from Bamboo. The structure of the fiber contains micro-gaps that allow for superior airflow and moisture wicking.
- Result: It keeps babies 3 degrees cooler in summer and warmer in winter compared to cotton. It works with the TOG rating to maintain a consistent, dry warmth, which is crucial for preventing eczema flare-ups triggered by sweat.
Read more: 4 Key Factors to Choose the Right Sleep Bag That Parents Need to Know
FAQ: Common TOG Questions from Parents
Can I use a blanket with a sleep sack?
No. A sleep sack is designed to replace loose blankets. Adding a blanket on top of a sleep sack increases the TOG rating unpredictably and poses a suffocation and entrapment risk.
What if my baby has a fever?
If your baby is unwell, their body temperature will rise naturally. In this case, you should dress them in lighter layers or a lower TOG rating than usual to help their body release the excess heat. Always consult your pediatrician for fever management.
Conclusion: Trust the TOG, Trust Your Instincts
At the end of the day, a TOG rating is a tool, not a rulebook. Every baby is different. Some run hot; some run cold. The charts and numbers are there to give you a safe starting point, eliminating the 2 AM guesswork.
Your goal is a "neutral thermal environment"—a fancy way of saying your baby should not be fighting to stay warm or cool. When they are comfortable, they sleep deeper, and (hopefully) so do you.
Ready to find the perfect temperature balance for your nursery?
Explore our collection of 1.0 TOG Bamboo Sleep Sacks — the ultimate year-round solution designed to keep your baby safe, snug, and sweat-free all night long.
