Experts have explained why you need to make a note of the date
Neil Shaw Assistant Editor
08:48, 19 Mar 2026Updated 11:35, 21 Mar 2026
Data shows the exact date
Temperatures are creeping up across the UK and many will face the common seasonal challenge of keeping cool at night. Experts at mattress and bedding specialist OTTY Sleep have calculated the exact date you should swap out your duvet – based on historical data.
OTTY has pinpointed an official date to swap to a lower tog in 2026 based on average temperatures across the country from the official start of spring – and it might be earlier than earlier than expected. The NHS advises an ideal sleeping temperature between 16C and 18C, which means that we should consider making the duvet switch on April 30.
From this date, temperatures are expected to start hitting 18C regularly and at this point a summer duvet will be adequate, according to the experts. Michal Szlas, founder of OTTY, said: “While there is no official rule on when to switch duvets, just guidance on ideal sleep temperatures from health organisations, we hope that our research can help Brits diarise a date to swap this year to prevent any unnecessary disruptions to sleep as the seasons change.
“Personal preferences and comfort levels will also play into the decision of course, understanding how you sleep best, the temperature that suits you and other seasonal bedroom changes you need to make are key to protecting sleeping patterns.”
Timothy Heran at Anglia Ruskin University told The Conversation: “Just before we fall asleep, our core body temperature begins a steep descent of roughly 1C to help us fall asleep. It reaches its lowest point during the first half of the night. On muggy summer nights this can make falling asleep difficult.”
Michal says there are three considerations to choose the perfect summer duvet:
1. A lower tog rating
“As the weather warms up, switching to a lower tog duvet can make a real difference to sleep quality. A summer duvet typically sits between 2.5 and 4.5 tog, which provides light coverage without trapping too much heat overnight.”
2. Breathable materials
“Breathability is key when it comes to staying comfortable at night during the warmer months. Look for breathable fillings and covers, such as cotton, bamboo, wool or moisture-wicking synthetic fibres. These materials allow air to circulate and help draw heat and moisture away from the body, keeping sleepers cooler and more comfortable overnight.”
3. Lightweight construction
“Many people underestimate how much the weight of their bedding can affect sleep. A lightweight duvet with evenly distributed filling feels airy and comfortable, helping sleepers stay cool and undisturbed even when temperatures rise.”