I grew up without air conditioning. My bedroom was on the second floor of a house that soaked up sun all day and radiated it back at me all night. I lay on top of my sheets at 2 a.m. rotating my pillow to the cool side every thirty seconds. It was miserable.

Now I live somewhere with AC but I still use these tricks because blasting the AC all night is expensive and dries out my sinuses. Here is what actually helps you fall asleep and stay asleep when it is too hot.

The cold water bottle trick

Fill a hot water bottle — the rubber kind normally used for winter — with cold water and a few ice cubes. Wrap it in a thin towel and put it at the foot of your bed. Your feet have a lot of blood flow close to the surface and cooling them down helps cool your whole body. This is the same reason you stick one foot out from under the covers in winter. It works in reverse too.

The frozen sock

Take a clean cotton sock and fill it with rice. Tie it closed. Put it in the freezer for a few hours. The rice holds cold for a surprisingly long time. Put it on the back of your neck or across your forehead — anywhere you have major blood vessels near the surface. I keep two in rotation so one is always frozen.

The damp sheet method

Run a flat sheet under cold water and wring it out as much as possible. You do not want a wet bed — you want a damp, cool sheet. Lay it over yourself like a blanket. As the water evaporates it pulls heat away from your body. This is the same physics that makes sweating work but amplified. Works best with a fan blowing across you — the moving air speeds up evaporation.

Strategic fan placement

Do not aim the fan directly at your body. Point it toward an open window from across the room. This creates a cross-breeze that cycles warm air out and pulls cooler air in. If you have two windows, put a fan blowing in at one window and a fan blowing out at the other. You just built a poor air conditioner.

What I tried that did not help

• Cold shower right before bed: It feels great for three minutes, then your body warms back up and you are just wet and still hot. A lukewarm shower actually works better — it lowers your core temperature gently without the rebound effect.
• Sleeping naked: Counterintuitive but fabrics wick sweat away. Bare skin just gets sticky. Light cotton or moisture-wicking sleepwear is better.
• Ice packs directly on skin: Too cold, too fast. Your body constricts blood vessels to protect itself from the cold and you end up trapping heat instead of releasing it. Wrap anything frozen in a thin towel.

I still use the rice sock and the hot water bottle trick every summer. They are nearly free and they work whether you have AC or not. The damp sheet method is saved for the truly brutal nights when nothing else cuts it.