How to dress a baby for a sunny day

Yes, a newborn can be outside on a sunny day, but not in the sun. Find shade: a tree, a parasol or the stroller canopy. Keep to the shade like this until your baby is 6 months old, in light clothes over the arms and legs and a soft sun hat. A young baby's skin is thin and can burn after a short time outside, and a baby can't crawl into the shade or tell you the sun is too strong.

Start with what the air temperature calls for, as on a cloudy day. The sun adds two things on top, and neither one is warm: a sun hat, and from 24°C (75°F) a sun cover shirt, a thin long-⁠sleeve shirt worn open over the bodysuit.

Loose, lightweight cotton or linen with a close weave covers the skin and stays cool. Long sleeves in the sun can still get warm faster than you expect. If the back of your baby's neck feels damp, move somewhere cooler and take off an extra layer (how to tell if your baby is too hot).

UPF on a clothing label works like SPF on sunscreen, only for fabric: the higher the number, the less of the sun's UV reaches the skin. Everyday clothes block some UV too, just less, and thin cotton lets even more through once it gets wet.

For a walk in the shade, everyday clothes are enough, as long as they cover the skin and you can't see through them. Tightly woven and darker fabrics block more than thin white cotton. A sun cover shirt or a UPF swimsuit earns its place where the shade runs out: at the beach, by the pool, or on a long walk with your baby in the carrier.

Pull the canopy all the way out. It shades from above and behind, but morning and afternoon sun comes in low under its front edge. You head out with the sun behind you and the canopy doing its job. Then you turn a corner, and suddenly direct sunlight is beaming straight under the hood into your baby's squinting eyes.

Take a second to step around and look at the stroller from the front. From behind the handlebar, you can't see the strip of bright light cutting across your baby's legs or face. Once the socks come off in summer, bare feet at the footrest are often the first thing in the sun.

If the seat turns around, turn your baby's back to the sun. For low sun, a clip-⁠on parasol or a canopy extension reaches where the hood stops (stroller sunshades). A parasol's shadow is small and moves with every turn, so set it again as you go.

When sunlight glares into the seat, the common reflex is to hang a muslin or a blanket over the front opening. Even a thin cloth cuts the airflow, and the seat heats up fast, so keep the opening clear (why a muslin is not a sunshade).

When you stop for a rest or a feed, park in deep, open shade with moving air. Patchy tree shade shifts across a bench quickly as the sun moves.

The carrier covers your baby's middle and your body shades the front, but the head, the lower legs and the feet stick out into the sun. The sun hat shades the head. Light pants that reach the ankles, or leg warmers, cover the shins, because bent knees pull the cuffs up. Thin socks cover the feet.

Keep to the shady side of the street, or hold a sun umbrella over you both. For a long stretch in open sun, a sun cover made for the carrier, in UPF fabric, covers the legs, with your baby's face left clear.

Your body warms your baby too, so on a hot day your baby may need lighter clothes than in the stroller (dressing a baby for the carrier).

A sun hat is shade that moves with your baby's head, so it has to cover the face, the ears and the neck. A baby sun hat needs a generous floppy brim or a long neck flap down the back. Baseball caps look cute, but they leave the ears and the neck folds bare.

Pick a brim soft enough to fold when your baby leans back against the stroller seat, the car seat or your chest, so it doesn't tip over the eyes.

Babies treat hats as optional accessories to be hurled onto the sidewalk, and a strap saves you from hunting for it every two blocks. Choose a hat with a short chin strap, or a cord and toggle at the back that holds it snug (which strap to choose). You can start the sun hat in the first months. Babies who wear one from early on get used to having it on, even if yours still pulls it straight off now and then.

Where there are no trees, bring the shade with you: a beach umbrella or a pop-⁠up shade tent, with room for you to sit beside your baby for a feed.

Sand, water and pale concrete bounce the sun back up into the shade, so the hat and the covering clothes stay on under the umbrella too. For the water, a long-⁠sleeve swim shirt or sunsuit in UPF fabric does the job an ordinary wet T-⁠shirt can't. Pack a dry outfit for afterward, because wet swim clothes get chilly on the way home.

The windshield usually blocks almost all UV. The side and back windows stop most of the rays that cause sunburn but let a good part of the UVA through, the kind that also damages skin. Sun through the glass heats a car seat fast, too. A rear-⁠facing seat often catches it through the back window, straight into your baby's eyes.

A blanket draped over the car seat traps heat just as it does over a stroller. Fit a mesh shade to the side window instead, and one to the back window for a rear-⁠facing seat, and pull the infant seat's canopy forward.