Quick answer

Choose a baby sleep bag by matching its TOG rating and fabric weight to your room temperature and the season. For warm months, pick a lightweight, footless sleep bag in organic cotton. For cooler weather, layer with a fleece or quilted sleep bag. Always ensure the sleep bag fits snugly around the chest and neck, with no excess fabric that could ride up.

Understanding TOG Ratings and Room Temperature

TOG (Thermal Overall Grade) measures a sleep bag's insulation. Lower TOG ratings (0.5–1.0) are for warm rooms (24–27°C / 75–80°F), while higher ratings (2.5–3.5) suit cooler rooms (16–20°C / 61–68°F). A 1.0 TOG sleep bag works for most seasons if you adjust the room temperature or add a layer underneath. Always check the room temperature with a thermometer rather than guessing.

For newborns, start with a 1.0 TOG sleep bag and adjust based on the season. Avoid heavy sleep bags for infants under 12 months, as they can overheat. If your baby feels sweaty or has a red face, remove a layer or switch to a lower TOG.

Materials Matter: Cotton vs. Fleece vs. Quilted

The fabric of the sleep bag affects breathability and warmth. Organic cotton sleep bags are ideal for warmer months because they allow air circulation and wick moisture. Fleece sleep bags trap heat and are best for cold winter nights. Quilted sleep bags, often filled with organic cotton, offer a middle ground—they provide warmth without overheating and work well for spring and fall.

For babies with sensitive skin, organic cotton is the safest choice because it's free from harsh chemicals. Pehr's sleep bags are made from GOTS-certified organic cotton, ensuring they are gentle on delicate skin. If you live in a climate with mild winters, a quilted sleep bag may be all you need year-round.

Fit and Safety: Sizing and Features to Look For

A properly fitted sleep bag should be snug around the chest and neck but loose enough for your baby to move their hips and legs. The armholes should be small enough that your baby can't slip through. Avoid sleep bags with hoods or extra fabric that could cover the face. Look for a full-length zipper for easy diaper changes, especially during nighttime wake-ups.

Footless sleep bags are great for active babies who are learning to crawl or walk, as they allow freedom of movement. They also help regulate temperature because feet can cool down naturally. For newborns, a sleep bag with a zipper that opens from the bottom makes middle-of-the-night changes less disruptive.

Decision Rules for Choosing a Sleep Bag

  • Match TOG to Room Temperature: Use a room thermometer and choose a sleep bag with the appropriate TOG rating. 0.5 TOG for hot summer nights (24–27°C), 1.0 TOG for mild seasons (20–24°C), 2.5 TOG for cool rooms (16–20°C). Avoid guessing based on your own comfort. Check the room temperature before every sleep.
  • Choose Fabric for the Season: Organic cotton for warm weather, fleece for cold winter nights, and quilted for transitional seasons. Always prioritize breathability to prevent overheating. Cotton in summer, fleece in winter, quilted in between.
  • Prioritize Fit Over Size: The sleep bag should be snug around the chest and neck but roomy at the hips. A bag that is too large can ride up over the face, while one too small can restrict breathing. Follow the weight and height guidelines, not just age. Snug at the top, roomy at the bottom.

Products That Help You Sleep Soundly

  • Ribbed Baby Footless Sleeper - Over the Moon: Cozy cuddles and all-day play! Our Ribbed Baby Footless Sleeper is made from GOTS certified organic cotton in a soft, stretchy rib knit that moves with your little one. With a comfy footless design, it’s perfect for early crawlers, tiny walkers, or warmer temps. A full-length zipper makes changes quick and easy, so you can spend less time fussing and more time snuggling. This footless sleeper is ideal for warmer seasons or active babies who need freedom to move. The organic cotton rib knit is breathable and gentle on sensitive skin, while the full-length zipper simplifies nighttime diaper changes.
  • Teddy Fleece Dropped Shoulder Sweatshirt - Rose Pink: The Teddy Fleece Dropped Shoulder Sweatshirt is the ultimate cozy layer for cooler days. Crafted from 100% GOTS Organic Cotton fleece, this unisex style features a relaxed fit for easy layering and everyday comfort. For colder nights, layering this fleece sweatshirt over a sleep bag adds warmth without restricting movement. The organic cotton fleece is soft and breathable, making it a safe choice for sensitive skin.

Who Should Use Which Sleep Bag

Best for

  • Parents who want a single sleep bag that works for most seasons with room temperature adjustments
  • Babies who are active crawlers or walkers and need freedom of movement

Not for

  • Parents who prefer a sleep bag with a hood or built-in blanket for extra warmth
  • Babies who sleep in very cold rooms (below 16°C) where a higher TOG or fleece layer is needed