Baby in a Heatwave: Safe Sleep, Strollers, Fans and Feeds

Short answer: In a heatwave, keep your baby out of direct sun, keep the room as close to 16–20°C (61–68°F) as you can, and dress them lightly: in very hot weather a short-sleeved vest or just a diaper is fine for sleep, with no blanket. Never cover a stroller or pram with a blanket or muslin, aim fans at the room rather than at your baby, offer milk feeds more often, and check for overheating by feeling the chest or the back of the neck.

Why are babies more at risk in a heatwave?

Because they can’t move away from the heat, take off a layer, or ask for a drink. The NHS lists babies and young children among the groups most vulnerable to hot weather, and the American Academy of Pediatrics (AAP) warns that a heat index of 90°F (about 32°C) or above, as defined by the US National Weather Service, can be dangerous, especially for babies and young children.

Heat can lead to dehydration, heat exhaustion and, rarely, heatstroke, which the AAP calls a medical emergency. Overheating during sleep is also one of the risk factors the Lullaby Trust and the AAP link to sudden infant death syndrome (SIDS), which is why sleep gets so much attention in hot-weather advice.

The good news is that the steps that protect babies are simple and mostly free: shade, fewer layers, a cooler room, and more feeds.

How should my baby sleep in a heatwave?

The same way as always, just with less on. The Lullaby Trust says a room temperature of 16–20°C (61–68°F) is comfortable and safe for sleep, and that in very hot weather it’s fine for a baby to sleep in a short-sleeved vest or even just a diaper. During a heatwave you may not be able to get the room that cool, and that’s OK. Do what you can, and dress your baby for the room you actually have.

Here’s a rough guide many parents use. It’s based on the Lullaby Trust’s advice, but no health body publishes an exact chart, so treat it as a starting point and check your baby:

Room temperature	What your baby might wear for sleep	Bedding
Around 20–22°C (68–72°F)	Short-sleeved bodysuit, or a lightweight sleep sack over a vest	Fitted sheet only
Around 23–25°C (73–77°F)	Short-sleeved vest, or a very light summer sleep sack	Fitted sheet only
26°C (79°F) and above	A diaper, or a diaper and a thin vest	Fitted sheet only, no sleep sack

For the full layer-by-layer breakdown at every temperature, see our guide on how to dress a baby for sleep by temperature.

1. Close curtains or blinds during the day. The Lullaby Trust and the NHS both suggest keeping the sun out of rooms during the hottest hours.
2. Open windows and the bedroom door at night if it’s safe to do so, to let cooler air move through.
3. Use a room thermometer. The Lullaby Trust notes it’s hard to guess a room’s temperature, especially when you’re hot yourself.
4. Strip the crib back. Firm, flat mattress, fitted sheet, nothing else. Skip the sleep sack if the room is very hot.
5. Place your baby on their back, for every nap and every night, just as in cooler weather.
6. Check the chest or back of the neck before you go to bed. If it’s clammy or sweaty, take off a layer.

Is it safe to use a fan or air conditioning for a baby?

Yes, as long as the fan isn’t blowing straight at your baby. The Lullaby Trust says you can use a fan to circulate air in the room but shouldn’t aim it directly at the baby. The AAP also advises keeping fans at a safe distance from children and not pointing them at yourself when the room is hotter than 90°F (32°C), because moving very hot air can add to dehydration rather than cool you.

Air conditioning is the most effective way to keep a room cool. If you don’t have it, the AAP suggests spending the hottest part of the day in a building that does, such as a library, a store, or a local cooling center.

A few practical points: keep fan cords and the fan itself out of reach of the crib, make sure a standing fan can’t be pulled over, and don’t hang a damp cloth over the crib to cool it.

Can I cover the stroller or pram to keep the sun off?

No. This is the single most repeated heatwave warning from the Lullaby Trust: don’t cover prams, strollers, or travel systems with blankets, muslins, or any cover that blocks airflow. A thin cloth feels like shade, but it traps heat inside, and the space under it can get much hotter than the air outside. Overheating is a risk factor for SIDS.

Instead:

• use a clip-on sunshade or parasol that leaves the sides open
• walk on the shady side of the street and plan outings for early morning or evening
• stay indoors in the hottest hours; the NHS puts these at 11am to 3pm
• check the chest or neck often, and take your baby out of the stroller into the shade if they feel hot

Babies under 6 months should be kept out of direct sun. Shade, a wide-brimmed hat, and light, loose clothing that covers the arms and legs come first. The AAP says that if shade and clothing aren’t enough, a small amount of sunscreen can go on small uncovered areas like the face and backs of the hands, while the FDA says to check with your pediatrician before using sunscreen under 6 months and the NHS says to keep young babies out of direct strong sunlight altogether. From 6 months, use a broad-spectrum sunscreen; UK guidance recommends at least SPF 30 with good UVA protection, reapplied often.

If your baby falls asleep in the stroller or car seat, the usual rule still applies: move them to a firm, flat surface on their back when you can. Our post on baby sleep in a swing or car seat explains why.

Does my baby need water in a heatwave?

If your baby is under 6 months and breastfed, no: offer the breast more often instead. Both the AAP and the Lullaby Trust say exclusively breastfed babies don’t need extra water before solids, though they may want to feed more often in the heat. The AAP adds that babies fed breast milk from a bottle can be given extra breast milk.

For formula-fed babies under 6 months, the advice differs by country. The AAP says babies should not be given water, especially in the first 6 months, and that formula-fed babies can have extra formula. The NHS and the Lullaby Trust say formula-fed babies may need small amounts of cooled boiled water between their usual milk feeds in hot weather. Both agree water should never replace feeds, and formula should never be watered down. Too much plain water can be dangerous for young babies, so ask your pediatrician what’s right for yours.

Once your baby has started solids, offer sips of water from an open or straw cup with meals and in between on hot days. Our guide on when babies can drink water covers amounts by age.

Signs your baby may need more fluids include fewer wet diapers than usual, darker urine, a dry mouth, and being unusually sleepy or fussy. In a newborn, compare against our guide to how many wet diapers a newborn should have.

How can I tell if my baby is too hot?

Feel the chest or the back of the neck. Hands and feet often feel cool even when a baby is warm, so they’re not a good guide. If your baby’s chest or neck is clammy or sweaty, the Lullaby Trust says to remove a layer and bring the room temperature down.

Other signs of overheating include flushed cheeks, damp hair, heat rash, and fast breathing. A sweaty head on its own is common in sleeping babies; our post on baby head sweating while sleeping explains when it matters.

To cool a hot baby down, move them somewhere shaded and cooler, take off extra clothing, offer a feed, and sponge their skin with lukewarm (not cold) water. The NHS says someone with heat exhaustion should start to feel better within about 30 minutes of cooling down. With a baby, don’t wait that long if anything seems wrong: call for advice.

For more on temperatures and when to call, see our guide on baby fever and when to call the doctor.

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