It finally feels like summer, with temperatures this weekend topping 30°C in parts of the UK. But tossing and turning in bed on a stiflingly hot night is nobody's idea of fun.
What you may not realise is that your mattress can make all the difference to how hot you feel. We test the insulation inside every mattress we review to help you pick the right one for your body temperature.
So before you resort to keeping hot water bottles in the freezer, read on to discover some of the best mattresses for staying cool and comfortable in bed.
Genuinely cool mattresses aren't always easy to find. Of the 135 mattresses we've tested, we've identified just 18 that feel cool to lie on.
The three mattresses we've picked out below are among them, meaning you can count on them to help keep you cool during spells of warm weather.
We've highlighted some of the coolest mattresses - but good temperature control isn't the only thing that matters in a mattress.
Prices are for a standard double mattress and are correct as of 27 June 2019.
This cheap Ikea mattress is proof that cooler mattresses don't have to be expensive. In fact, the price looks a little too good to be true, even if it does have a slightly more basic open-spring structure, rather than full-blown pocket springs. But we've found that mattresses don't need to be luxurious to provide excellent and long-lasting support for your spine.
We've tested more cool mattresses from John Lewis than any other brand, and this one is among the coolest and cheapest.
Unlike many modern mattresses, this one is two-sided so you'll need to flip it regularly. It has a pocket-spring core, and all the additional comfort layers are made from natural materials, such as wool. But lots of mattresses with similar structures struggle with sagging in our durability tests.
Find out whether this one can stand the test of time in our John Lewis mattress review.
Don't assume that mattresses containing foam or memory foam always feel warmer to lie on. This one contains layers of foam on either side of the pocket-sprung core, but it's still one of the coolest mattresses we've seen. It's also one of the firmest.
We don't just rely on the subjective opinion of our mattress testers after lying on each mattress - we go the extra mile with our tests, so you can be sure you're picking the right mattress for your body temperature.
We use a climactic chamber where the temperature and humidity is always consistent. Then we apply heat to the mattress and measure how much it absorbs. The coolest mattresses let most of the heat pass through, while the warmest store it up.