We’ve all been there: It’s bedtime on a warm summer night, and the fan just isn’t cutting it, so you crank up the AC just to end up shivering in bed. Temperature, unsurprisingly, is one of the most important factors influencing your sleep quality. Here, an expert breaks down what you need to know to create the best bedtime environment.

What temperature should your room be?

“Generally, cooler temperatures are recommended in the bedroom,” explains sleep researcher Christine Blume. Your body temperature naturally drops over the course of the evening, and a cooler environment helps you expend less energy releasing heat.

“The ambient temperature should be cooler than the body temperature,” Blume says. This is why many people fall asleep—and stay asleep—better in slightly cooler rooms. According to the Cleveland Clinic, temperatures between 60 and 67 degrees Fahrenheit are considered ideal.

There is a caveat, though. Your body’s heat loss occurs primarily through the fine networks of blood vessels in your hands and feet, which lie very close to the skin’s surface, according to Blume. These blood vessels dilate (widen) in the evening, allowing heat to be released more easily. When your feet are cold, “the heat dissipation doesn’t work well,” she explains, and the body remains active rather than gradually transitioning to sleep mode.

This also explains why it can be challenging to fall asleep when the room is below 60 degrees: Your body is under stress as it tries to maintain a stable core temperature.

What other factors can influence your sleep quality?

There are a few strategies to help you sleep better. Just like you’d think about your mattress quality, your comforter can play a role in your sleep. “Up to a certain point, we can regulate temperature through the insulation of the comforter,” Blume says, but it can be beneficial to use comforters where the weights align with the seasons.

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