Tog ratings are a rough measurement used in the UK to help you understand how warm a duvet may be.During the summer months, a 4.5-tog duvet is considered extra lightweight and comfortable, depending on a number of factors including how your house or mattress holds heat or how warm-natured you are.Depending on those factors, a 10.5-tog duvet may also suit you (and would likely serve you well throughout the year) or you may prefer to keep your bedding incredibly lightweight with a 1.5-tog option.Togs guide you to making the right choice, but it’s not the only way to determine what tog duvet is perfect for summer. Ultimately, it comes down to what materials work best for your body.