Baby Sleep in the Heat: How to Keep Your Little One Cool and Safe
Baby sleep heat challenges are real — and with an unusually hot Bank Holiday weekend arriving in May, many parents across the UK are struggling. First, know that you are not alone
Warm nights genuinely affect babies, and the good news is that a few simple steps can make a big difference.
Below, our experts at Millpond Sleep Clinic share everything you need to know.
Why Temperature Affects Baby Sleep in the Heat
The ideal sleeping temperature for a baby is between 16°C and 20°C. So, when the mercury climbs above this — as it can easily do during a May heatwave — sleep quality drops quickly. Babies cannot regulate their body temperature as efficiently as adults. As a result, they wake more often, settle less easily, and become overtired.
Crucially, overheating is also a known risk factor for Sudden Infant Death Syndrome (SIDS). That is why our safer sleep advice always includes guidance on room temperature. In short, keeping your baby cool is about safety, not just comfort.
How to Cool Your Baby’s Room Before Bedtime
First, focus on the room itself. Even small changes to the environment can bring the temperature down by several degrees.
Close curtains and blinds early
Start this first thing in the morning. Blackout curtains or blinds are particularly effective because they block solar heat from building up throughout the day. As a result, the room stays several degrees cooler by bedtime.
Keep windows closed during the day
This surprises many parents, but it works. If the outside temperature is higher than inside — which is common during a UK heatwave — open windows to let hot air in. Instead, keep them shut until the evening, then open them once the outside air cools down.
Use a fan wisely
A fan is helpful, but position it carefully. Place it near an open window to draw cooler night air into the room. Importantly, never point it directly at your baby. Also, run it for 20–30 minutes before the bedtime routine begins so the room is already cooling when your baby goes down.
Use a room thermometer
Because 16–20°C can feel cooler than expected, a room thermometer removes the guesswork entirely. Check it before each sleep and adjust clothing and bedding accordingly.
Millpond tip: Pre-cool the room as early as 6 pm. Close the door to hold the cool air in, then begin your bedtime routine in a separate room.
Tips for Baby Sleep in the Heat at Night
Once the room is as cool as possible, turn your attention to your baby directly. Here are the most effective ways to keep them comfortable throughout the night:
- Give a lukewarm bath before bed. Avoid cold water, as this can cause the body to retain heat. Instead, aim for a temperature that feels gently cool on your wrist.
- Dress your baby in one light layer of cotton sleepwear — or simply a nappy on very hot nights. Natural fibres breathe far better than synthetic ones.
- Switch to a 5 tog summer sleeping bag. This is lightweight enough for warm nights but still provides a familiar, safe sleep environment.
- Check the temperature by feeling your baby’s chest or back, not their hands or feet. Hands and feet are naturally cooler and will mislead you.
- Remove layers if your baby feels hot or sweaty. Never add extra layers “in case it gets cold later” — overheating is a greater risk than being slightly cool.
For more guidance on safe sleep, see our sleep advice videos.
Keeping Your Baby Hydrated in Hot Weather
Hydration is an important part of supporting your baby’s sleep in the heat. Babies dehydrate faster than adults, so feeds become even more important in warm weather.
- Breastfed babies: offer feeds more frequently. Your breast milk will naturally adjust to provide more thirst-quenching foremilk. No extra water is needed before six months.
- Formula-fed babies: alongside regular milk feeds, you can offer small amounts of cooled, boiled water from around six months.
- Expect more night waking: your baby may wake more often simply because they are thirsty. This is completely normal in hot weather and should settle once temperatures drop.

Bank Holiday Weekend: Protecting Sleep When Routine Is Disrupted
A Bank Holiday heatwave brings extra challenges. For example, days out, later bedtimes, and more stimulation can all affect how well your baby sleeps. Here is how to manage:
- Try to keep nap times as consistent as possible, even if the timing shifts by 20–30 minutes.
- Consider an earlier bedtime if your baby has had a busy or hot day. Overtiredness makes it much harder for babies to settle, especially in the heat.
- If you are staying away from home, bring your baby’s usual sleep cues: their sleeping bag, a comforter, and a small fan. Familiarity helps enormously in an unfamiliar room.
- Finally, do not worry if sleep is not perfect over the weekend. Return to your normal routine on Tuesday, and most babies will resettle within a night or two.
Signs Your Baby May Be Too Hot
It is important to know what to look for. According to the Lullaby Trust safer sleep guidance, signs of overheating include:
- Flushed or red skin
- Rapid or noisy breathing
- Unusual restlessness or crying
- Feeling hot and sweaty on the chest or back
If you notice these signs, remove a layer immediately and offer a feed. If you are concerned, contact your GP or call NHS 111. You can also read the NHS advice on babies and hot weather for further guidance.
In Summary: Baby Sleep in the Heat
To sum up, helping your baby sleep in the heat takes preparation, but it is absolutely manageable. So, start by cooling the room early, dressing your baby lightly, using a room thermometer, and offering extra feeds. Give yourself grace over the Bank Holiday weekend — a few disrupted nights will not undo good sleep habits.
However, if sleep difficulties continue beyond the heatwave, we are here to help. Millpond Sleep Clinic has been supporting families with gentle, evidence-based sleep packages for over 30 years. Get in touch to find out how we can support you.
By Mandy Gurney RGN, RM, DipHV — Updated May 2026























