It's no surprise that trying to get shut eye without the help of an air conditioner can be tough.
But what people may not realize is that a warm room can mess with your body even after you've managed to fall asleep.
Past studies have shown that the optimal temperate for sleep is quite cool, around 60 to 68 degrees.
Cooler temperatures can help facilitate a decrease in core body temperature, which initiates sleepiness.
That temperature should reach its lowest point several hours before we wake.
But if the body never gets a chance to really cool down, sleep can be disrupted.
Rush neurologist Roumen Balabanova says the heat can interfere with important phases such as REM sleep, which is why people may wake up feeling less than refreshed.
"As you know sleep goes through different phases and during the REM sleep the temperature goes down and there may be an interference of this phase, and so this transition to non-REM sleep may be affected," said Balabanova.
Finding ways to cool the body can help.
Some experts recommend taking a cool shower or bath right before climbing into bed.