Please, see some references in another reply. In facts you can lower your temperature artificially. Your body implements some mechanics to do that. For example

Please, see some references in another reply. In facts you can lower your temperature artificially. Your body implements some mechanics to do that. For example late in the afternoon, your temperature reaches its peak and starts to drop again. That drop in temperature of one to three degrees is vitally essential for falling asleep quickly and you actually can accelerate that drop! Although it’s somewhat counterintuitive, hot baths or showers or a sauna one or two hours before your bedtime will help to decrease your temperature. If you get into a sufficiently high temperature of water for about 15-20 minutes and then get out of it, your body will employ particular mechanisms for cooling itself and your body’s temperature will drop more quickly. That will allow you to fall asleep more easily. As for the cold shower. When the cold water hits your body, it constricts faster circulation of your blood in your deeper tissues and helps to maintain ideal body temperature. Also, you could try to control your morning temp minimum by establishing sleep consistency and changing your average wake up so that your temp minimum falls into the time you want it to fall.