The Exact Date You Should Change Your Duvet For Autumn, According To An Expert

If there’s one thing we love to do in Britain, it’s debate and discuss the weather. I actually think it’s very sweet and inevitable – we really do experience the drama of all four seasons on this little island so of COURSE we talk about it!

When it comes to this time of year, though, these debates move on to when it’s time to put the heating on and when it’s time to switch to heavier duvets to get us through those long winter nights.

This also brings with it the key question of… what tog rating duvet should we even be getting? Thankfully, the experts at UK retailer M&S have shared their tips for perfecting your autumn duvet routine.

Melissa Goldman, senior buyer at M&S comments: “A tog (thermal overall rating) measures the thermal insulation of bedding. The higher the number, the better the duvet will retain heat and keep you warm.

“As a general rule of thumb, we recommend changing your duvet in line with outside temperatures to ensure optimal sleep quality.”

So, thankfully for those of us who aren’t in-the-know, the experts have created a guide on tog ratings.

• For temperatures above 18°C, the ideal tog rating is 4.5 or lower
• For temperatures between 15 -18°C, 7.5 to 10.5 tog is ideal
• For temperatures under 15°C, 10.5 and higher togs are best

Goldman adds: “The lightest duvets (anything below a 4.5 tog rating) are best suited to the summer months when temperatures frequently exceed 18°C. Duvets ranging between a 7.5 and 10.5 tog rating are best for transitional seasons like spring and autumn and 10.5 duvets are ideal for winter.

“While a 10.5 tog duvet is sufficient for most modern homes with central heating, for those who feel the cold especially at night, a 13.5 tog duvet is a good option for the coldest winter months.”

The experts at M&S have analysed weather data from 2025 to reveal the exact dates people in the UK should change their duvet.

Goldman advises: “The 20th September has been revealed as the date when UK households should switch their duvet for autumn.

“Last year, temperatures fell below 18°C on this date and didn’t rise above that point again for the rest of the year, marking it as the ideal time for people in the UK to swap their summer duvet for a 7.5 to 10.5 tog duvet.”

If you want to transition to a thicker duvet again for winter, she suggests 7th November, saying: “Temperatures dropped below 15°C on this date in 2025 and remained there or below until year-end, making this the perfect time to switch to a warmer winter duvet of 10.5 tog or above.”