September is the UK’s most popular month for births – but after an exceptionally hot summer and with the Met Office warning that hot spells could return, mums-to-be may need to rethink the traditional autumnal newborn checklist.

September has long been Britain’s baby boom month, with more babies born in September than any other month, according to analysis by the Office for National Statistics. For parents expecting a September arrival, that traditionally means preparing for the start of autumn – cosy sleepsuits, extra layers and cooler nights.

But as UK summers get hotter, the way families prepare for a September baby may be changing too. Pramworld, one of the UK’s leading nursery retailers, is advising families to think beyond the season when preparing for their new arrival, particularly when it comes to clothing, sleep and getting out and about.

The advice comes after a summer that has pushed the UK’s weather to extremes. 2026 is on course to be the UK’s warmest summer on record, with the average UK temperature between 1 June and 10 August reaching 16.48°C – 1.88°C above the 1991–2020 average. England has been warmer still, with an average summer temperature of 18.19°C so far – 2.46°C above average.

For families expecting a September baby, autumn may be on the calendar, but the weather could still feel very much like summer.

And the heat may not be over just yet. While September could begin unsettled, the latest Met Office outlook says warmer and potentially hot spells remain possible later in the month, particularly across southern parts of the UK.

For mums in their final trimester, that could mean spending the last weeks of pregnancy in temperatures more familiar to the height of summer – before bringing a newborn home into potentially warm September weather.

So, is it time to rethink what it means to prepare for an ‘autumn baby’?

From what baby wears and sleeps in to staying cool in the pram and travelling safely in a warm car, Pramworld Director David Winstanleyshares practical advice for families preparing for a September arrival – including how to adapt the traditional newborn checklist for increasingly unpredictable weather.

When autumn still feels like summer: preparing for a September baby

September sits in an awkward spot for new parents. It may officially mark the start of autumn, but after increasingly hot UK summers, the weather when baby arrives can be anything but autumnal.

For families expecting a September arrival, David Winstanley, Director at Pramworld, shares some practical considerations for those first few weeks – from what baby wears and where they sleep to getting out and about safely in warmer weather.

1. Dress for the temperature, not the month

“September can still bring some surprisingly warm days, so it’s worth having lightweight, breathable clothes to hand rather than putting away your summer essentials as soon as autumn arrives. At the same time, the weather can turn quickly, so having a few warmer layers means you’re covered either way. The key is to dress baby for the temperature outside, rather than the season on the calendar.”

2. Don’t assume September nights will be cool

“It’s easy to assume that once September arrives, the evenings will automatically be cooler, but after a hot summer, homes can stay warm well into the night. A room thermometer is a useful way to know the temperature rather than guessing, so you can adjust baby’s clothing and bedding accordingly. The Lullaby Trust recommends keeping the room where a baby sleeps between 16°C and 20°C, so it’s worth keeping an eye on this even as we head into autumn.”

3. Think about shade as well as warmth when you’re out

“When you’re out with a newborn on a warm day, keeping them shaded is important, but covering the pram with a blanket or muslin can trap heat and restrict airflow. A proper sunshade or parasol is a much safer option, as it keeps baby shaded while allowing air to circulate and lets you keep an eye on them. It’s also worth regularly checking the back of their neck or chest to make sure they’re not getting too warm.”

The Lullaby Trust advises against covering prams, buggies and travel systems with blankets, muslins or other coverings, as these can restrict airflow and increase the risk of overheating. It recommends using a suitable sunshade or parasol and keeping babies out of direct sunlight as much as possible.

4. Remember that cars heat up quickly

“If you’re travelling with a newborn in warm weather, remember that cars can heat up quickly, even when it doesn’t feel particularly hot outside. For longer journeys, build in regular breaks to check on baby and take them out of their car seat for a stretch. And once you reach your destination, if they’ve fallen asleep, move them onto a firm, flat surface rather than leaving them in the car seat.”

The Lullaby Trust advises taking regular breaks during longer journeys to check on baby and take them out of their car seat. Car seats are designed for travelling, rather than as a main sleeping place.

5. Keep safer sleep advice the same, whatever the weather

“September weather can be unpredictable, but the basic safer sleep advice stays the same, whatever the temperature. There’s no need to add extra blankets or padding to a cot to make it cosier – a firm, flat mattress is safest. If it’s warm, focus on keeping the room cool and dressing baby appropriately for the temperature, while keeping the sleep space clear and following the same safer sleep routine.”

The Lullaby Trust recommends placing babies on their back, on a firm, flat mattress, for every sleep, including when away from home.

Is the ‘autumn baby’ checklist changing?

September may mark the beginning of autumn on the calendar, but the weather doesn’t always agree.

With September remaining the UK’s most popular month for births, this year’s baby boom could be arriving into anything from late-summer sunshine to more traditional autumn weather.

For parents, that doesn’t mean abandoning the autumn essentials. It simply means being prepared for both – because when it comes to a September baby, the calendar doesn’t necessarily tell you what the weather will bring.