Marks & Spencer has identified November 7 as the ideal date for UK households to switch to a thicker duvet for winter, based on an analysis of last year's weather data.
The retailer reached that date after examining 2025 figures, which showed temperatures dropping below 15°C on November 7 and staying at or below that level for the rest of the year.
Recommended tog ratings
Melissa Goldman, senior buyer at M&S, said: "November 7 has been revealed as the date when UK households should switch their duvet for winter." She recommended a duvet rated at 10.5 tog or above for the colder months, noting that the best option depends on individual needs and bedroom conditions.
A duvet's tog rating measures how well it insulates and retains heat, with higher ratings generally providing more warmth. M&S advises that a rating of 4.5 tog or lower suits temperatures above 18°C, while 7.5 to 10.5 tog is recommended for temperatures between 15°C and 18°C. When temperatures fall below 15°C, the retailer recommends 10.5 tog or higher. For those who feel particularly cold at night, Ms Goldman says a 13.5 tog duvet could be a more suitable choice during the coldest part of winter.
A guide, not a guarantee
November 7 is a retailer's recommendation based on last year's weather patterns, rather than an official deadline that applies to every home. Outdoor temperatures do not necessarily reflect conditions inside a bedroom, where heating, insulation and personal preferences can all influence how warm someone feels.
The Met Office's review of November 2025 also highlights how variable UK weather can be, with a mild start to the month followed by colder conditions later on. This underlines why a date based on one year's temperatures should be treated as a guide rather than a guarantee of when the weather will turn cold.
For better sleep, the NHS recommends making the bedroom comfortable, quiet, dark and cool. The right duvet can help maintain comfort overnight, but anyone who tends to overheat may prefer a lighter option rather than automatically choosing the thickest available.
Households can use the advice as a prompt to check their bedding before winter sets in. Anyone already feeling chilly under their current duvet can switch sooner, rather than waiting for the suggested date.
