Summer with a newborn is wonderful — long evenings, the smell of warm air through the window, tiny toes in the sunshine. It's also, if we're honest, slightly terrifying when you're not sure whether they're too hot or too cold.
I've dressed six babies through various British summers, and I've learned a thing or two about what actually works. Here's my practical guide to newborn summer dressing — no fluff, just what you need to know.
The Golden Rule: One Layer More Than You
This is the piece of advice that gets repeated everywhere, and it's repeated everywhere because it's true. Newborns can't regulate their body temperature like we can, so as a starting point, dress them in one more layer than you're wearing.
That said, in a genuine UK heatwave (it does happen!), this rule softens a little. If you're in shorts and a thin top and you're still warm, a single light bodysuit or a thin romper is usually enough for your baby.
What to Dress a Newborn in on a Warm Day
Light Cotton Bodysuits and Rompers
A short-sleeved cotton bodysuit or romper is your best friend in summer. Look for 100% cotton — it breathes, it washes well, and it's gentle on new skin. Pop them in a thin one and you're done.
Our rompers at Milkmoon are made from soft, breathable fabrics chosen specifically because they're gentle on delicate newborn skin. Nothing synthetic, nothing stiff.
A Thin Cardigan for Cooler Moments
Even in summer, you'll want something to layer. Air conditioning in shops and cars can be surprisingly cold, and evenings cool down quickly. A thin knitted cardigan that can go on and come off easily is the most useful thing you can own.
A Soft Hat for Outdoors
If you're out in direct sunlight, a soft cotton hat is essential. It shades their face and head — both of which are vulnerable to the sun. Keep it light and breathable, and look for a brim if you can.
How to Tell If Your Baby Is Too Hot or Too Cold
Check the back of their neck or their tummy — these give you a much more reliable reading than hands and feet, which are often cooler than the rest of the body.
- Too hot: skin feels sweaty or clammy, they look flushed, or they're unsettled
- Too cold: the back of the neck feels cool to the touch
- Just right: warm and dry
If you're unsure, err on the side of removing a layer rather than adding one in warm weather.
What to Avoid in the Heat
- Synthetic fabrics — they trap heat and don't breathe the way cotton does
- Overdressing out of habit — it's easy to reach for the usual layers without thinking
- Leaving them in direct sunlight — the NHS advises keeping babies under six months out of direct sun altogether
- Too-tight clothing — it restricts airflow and makes everything more uncomfortable
A Note on Night-Time in Summer
Night dressing is where a lot of parents find themselves stuck. A good guide is to use a baby sleeping bag with a tog rating that suits the temperature — in summer, a 0.5 or 1.0 tog bag with a short-sleeved bodysuit underneath is usually right. You don't need sheets or blankets, which reduces the risk of overheating.
Summer Clothes for Newborns at Milkmoon
We stock a lovely selection of light summer pieces for newborns — soft rompers, two-piece sets, and little outfits that are practical for warm days without sacrificing any of the cuteness. Everything is chosen by me, and everything is something I'd dress my own babies in.