Your body temperature changes when you sleep. remember sleep follows your core body temperature. Rhythm your core body temperature will rise in the evening time till about 10 30 at night. where it’ll hit a peak. it will then begin to drop and that drop is a signal to your brain to release melatonin therefore without temperature change you have no sleep. Another interesting question is
how does heat affect sleep? 
exposure to heat will cause a decrease in both your deep sleep and your physical restoration and REM sleep and your mental restoration. this will occur mostly during the first sleep cycle of the night and less frequently in later Cycles. your body does not do well sleeping in the heat after several nights of exposure and research now theorizes that our bodies need us to wake up after being exposed to heat to maintain a consistent core temperature. Also, remember high humidity levels can compound this effect. now the opposite question might be well.
how does cold affect sleep?
turns out cold exposure primarily impacts sleep later in the night when REM sleep is more dominant than deep sleep. One quick trip that everyone can use if the cold is affecting their sleep. try wearing socks many people don’t realize they have lost a tremendous amount of heat through their feet and this is a quick way to warm up without piling on the covers now one of the top questions I get is.
Is there a best temperature for Sleep?
somewhere between 65 and 75 degrees appears to be Optimum for most people now this is going to depend on what part of the country you’re living in and the relative humidity. if your room temperature drops below 65 your body will want to shiver to create heat and that would wake you up out of REM sleep when you’re paralyzed if the room temperature goes above 75 degrees the brain will wake you up to remove the covers and get more air.
how can you maintain an optimal sleeping temperature? 
- set the thermostat somewhere between you can 66 to 70 degrees Fahrenheit at night experts consider this temperature range to be the best for sleeping. if you find yourself feeling too hot or too cold Within These parameters slightly adjust the dial to reach your ideal temperature.
- keep the bedroom well-ventilated. Natural ventilation has been linked to better quality sleep, particularly during the
transitions between seasons in places with mild climates. people also tend to sleep better in bedrooms with fresh air. - Take an evening shower or bath. showering or bathing in warm water before bed produces a cooling effect that can help you fall asleep more quickly and stay asleep longer this Cooldown has also been associated with more deep sleep and better overall Sleep Quality. bathing one to two hours before bed is usually what’s recommended.
- Block out sunlight. closing the blinds Shades or curtains can keep rooms cooler during the hot weather keeping the windows covered can also help your bedroom stay warm when it’s cold outside.
- Try different types of pajamas and bedding add or remove types of bedding as needed to feel comfortable during the different seasons also remember to consider testing out different sleepwear Fabrics one study found people were likely to fall asleep faster while wearing wool clothes as compared to Cotton garments.