How to Sleep Comfortably on a Hot Night

1. Plug in your fan and turn it towards you. Purchase a commercial bag of ice cubes. Empty the entire bag into a wide, shallow container (to contain the water as the ice melts) such as a roasting pan. Place the container of ice right in front of the fan (between the fan and you), at the level of the top of the bed. The ice-cooled air will be noticeably cooler than the room air for the amount of time it takes for the ice to melt -- which is as long as it should take for you to fall asleep!
2. 

   The towel method
   Try the towel method. Hang a wet towel from two chairs to hold the ice. The melting ice will wet and chill the towel and the fan will blow that cold air on you. Place a container under the towel to catch the melting ice water. You can use a thread to connect the bottom of the towel with the container to avoid the annoying dripping sound.
3. A cool shower will do wonders
   Take a cool shower, bath, or wipe your body down with a cool wash cloth. Without fully drying yourself, hop into bed, and let the air slowly dry you. This will keep you cool for a long time, allowing you to fall asleep. If a shower or bath is not an option, splash cool water on your head, and soak your hands and feet in cool water if possible. Your head, hands and feet are your "radiators" and you'll feel cooler faster by focusing on those areas. Note that this method is temporary, and more psychologically sound than physiologically accurate, as a cold shower will close your body's pores, which in the long run will heat your body.
4. Consider using the "Egyptian Method": wet a sheet or bath towel that is large enough to cover you with cool or cold water, and wring it or run it through the spin cycle on a washing machine until the sheet is quite damp but not dripping wet. Place the dry towel or sheet on your bed underneath your body and use the wet sheet as your blanket. The damp blanket will keep you cool. Or, during an extreme heat wave, take a light t-shirt, wet it, wring it out and wear it. Evaporation from the shirt will help to keep you cool enough to sleep for a few hours. This is a very simple and environmentally friendly method of staying cool.
5. Take a pair of cotton socks, rinse them in cold water and wring them until they are damp and put them on. Cooling your feet lowers the overall temperature of your skin and body.
6. Sleep in a 'spread eagle' position, and think cool thoughts.

Tips

• Keep a glass of ice cold water close to your bed so that in the event that you wake up hot and uncomfortable, you can easily cool off again without having to get up.
• The type of material that you sleep in and on will affect how hot you get. Porous materials breathe better and will help you to avoid getting sticky. A light cotton shirt and light cotton shorts work well. Sleeping naked can actually make you even more hot since it doesn't allow moisture to evaporate between your body and the sleeping surface, however, if you don't cover yourself with heavy blankets and are absolutely sure no one who you wouldn't want to see you nude will walk in at some point in the night or in the morning, you can sleep without clothes and have decent results. Keep in mind, though, this might not always help.
• When sleeping in a hammock, air flows over your whole body. A bed absorbs your body heat and keeps you hot. Get out that hammock you bought in Cancun and try sleeping in it with a fan blowing on you.
• Another possibility is to purchase a Bedfan, although it is more expensive.
• If you have a waterbed, turn the heater on the waterbed way down. Lay down on the surface of the waterbed. Even if it's 85°F (29°C), your body is 98°F (37°C), and the heat transfer rate for direct contact is about 100 times larger than for convection. It can make you so cold you may shiver. Be aware that temperatures set below 85°F can lead to hypothermia with prolonged contact.
• Keep the door to your bedroom open, so that there is proper air circulation from other rooms.
• Partly fill a plastic bottle with water and freeze it. Put it in front of a fan; it'll give the same effect, but is less likely to spill.
• Make a Rice Sock and place it in the freezer and leave it there for at least two hours. When you turn in, bring the bag with you to use as a cool compress. Try placing it under your pillow so it's nice and cool when you flip it over.
• If you have curtains made from a light material, like muslin or net, soak them with water (or put them through the washing machine and rehang them). Any breeze at all that blows through your window will immediately be vastly cooler.
• Still another option is to get a large powerful fan, such as one at least 16" in diameter and put it facing outward in a window in another room than the one you are sleeping in. Then, close all other windows in the house except the one the fan is in, and where people are sleeping near. The fan will exhaust hot air out of the house or apartment and create a vacuum which will pull in the cooler night air from the outside through the open windows where people are sleeping. Prop the doors in the bedroom(s) somewhat ajar to create a path for air to migrate. This is much more effective than having a loud fan blowing the same hot room-temperature air back at you. This of course assumes it is night time and that it has become significantly cooler outside than during the day when your home warmed up. If you have a lot of people sleeping or you want more airflow, get a more powerful fan, or put another exhaust fan facing another open window.
• If you have a hatch to the loft or attic, leave it open at night. That will give the heat trapped in the house somewhere to escape to, since hot air rises.
• If you live in a less humid climate, you can usually find small, portable swamp coolers at hardware stores for about $100. These need air flow. Place one in front of a window, and place a fan in the doorway, blowing air out of the room.
• Lightly mist a top sheet, and place it in a plastic bag in the freezer. Pull it out just before you're ready to sleep. It'll keep you cool enough to fall asleep.
• Sleep with your feet out from under the sheets, body heat will escape via your feet.
• Use a smaller, firmer pillow, to allow more air circulation around your head, which is the hottest part of your body. An extreme option would be one of those African "pillows" that are unpadded carved wood braces that hold the head. A more comfortable choice is a cool and relaxing smelling Japanese-style Jasmine and Buckwheat pillow.
• Use a drywall wall as a cool surface.
• Give yourself goosebumps by lightly dragging your fingers across your skin.
• For goosebumps AND cooling, fill a spray bottle with very warm-to-hot water. Spritz behind your knees, on your feet, and anywhere that's sweaty. The hot water keeps you from being shocked when you spritz. Now, go get in front of a fan!
• Try sleeping on your side to help keep your body cooler.
• For the first and second mentioned methods, you might try pouring salt on the ice and using a combination of ice and salt water to begin with. Brine freezes at much lower temperatures than fresh water; the temperature difference will be greater, thus taking more time to even out and melt the water.
• Use a cold compress or ice bag on the neck or between the thighs to cool the blood in major veins.
• Remember, you lose heat quickest through your extremities, such as your feet. So on very hot nights, remember to not wear any socks, it will make you considerably cooler. You also lose heat from your head, so keep your hair wet.
• For those who cannot sleep without something draped over them, an empty duvet works well. A duvet works like a pillowcase for a down comforter - just use it without the comforter.
• It is a good idea to get air conditioning if you don't have it already-- this is because it is definitely worth it.
• Drinking warm milk relaxes you and helps you sleep.
• Place a fan at the foot of your bed, and stretch the topsheet over the top. The air will blow in between the sheets and lift up the top-sheet a bit. Looks like the scene is Ghostbusters with the Keymaster and Gatekeeper, but keeps you very cool!
• Fill a hot water bottle with cold water from the fridge and put it on your ankles and feet - it works!
• Place your wrists under the cold tap for about 30 seconds. the blood that flows near the surface of the skin will cool and it will make you feel cool. alternatively, get a wristband and drench it with water. this will also have the same effect.
• For all of the evaporative methods (damp whatever), air circulation is needed. Just leaving a window open is good enough. The air will otherwise soak up all the moisture it can hold and you'll stop cooling.
• Acclimating yourself to warmer weather is much better (and better for you) than running the A/C all the time.
• Try to acclimate yourself to an even warmer climate than your bed just before going to sleep. For instance, hang out in your warmer, less ventilated living room just before retiring to your cooler bedroom.
• Consider sleeping in a tree. Have you ever seen a squirrel sweat?

Warnings

• Spending lots of time in the direct draft of a fan can cause severe dehydration.
• A bath or shower that is very cold might not be suitable for people who have various medical conditions. To be safe, take a cool or slightly warm shower.
• Lowering the temperature of a water bed may make it colder than the room temperature. When that happens, the humidity in the air will begin to condense into water on the plastic. Water then soaks the foam layer and combined with dead skin cells makes a great medium for mold, especially when, months later, you turn up the heat for the winter. Recommend that you fold back the top foam mattress layer if you want to use the cold bladder as a giant ice pack, then add some sheet to soak up the condensed sweat next to the plastic. Then wash the sheets.
• Be careful that you keep the fan and its cord at a higher level than the melting ice water—you don't want to cause an electric accident, now.
• Never do any physical activity before you head off to bed, this will make your blood pump fast, and in turn make it difficult to sleep.
• Wipe off the fan before use and also do not place the fan extremely close to your face. If a dirty fan is near your face, this may cause sinus colds in the morning because of the dust particles.

Things You'll Need

• Bag of ice cubes
• Shallow container
• Fan
• Salt water