Sleep and heat are not friends. In fact, our bodies need a cool environment in order for the best sleep. As a guide, 15-18 degrees centigrade (59-64 Fahrenheit) is the range you want your room temperature in. The following tips may help when that's just not possible due to particularly warm summer days.
1. Keep curtains and blinds shut in the bedroom all day to prevent direct sunlight from getting into the room.
2. At night try to create a cross breeze - with several windows open in and near to the bedroom (doors open). If you live in a house with a loft/attic, you can leave the door to this open to allow warm air to move upwards and increase the cross breeze.
3. Place bowls of ice near to any fans, so that the air is being blown through/over the ice.
4. Give your child a very warm bath before bedtime. Contrary to popular opinion that cool/luke-warm baths are the way to go, actually a warm bath makes the biggest difference to body temperature, by temporarily increasing it, encouraging a bigger drop once out (which can also help to trigger melatonin - sleep hormone - release).
5. Consider making milk popsicles, by freezing expressed milk/cows milk. for a quick, cold hit at night.
6. If possible get some bamboo sheets and sleepwear, for the coolest experience. If not, make sure everything is 100% cotton (no polyester blends).
7. Put your child to sleep in just a short sleeve vest, not just a nappy. Bizarrely a thin/small layer of clothing can help to regulate body temperature better than just a nappy/totally bare skin.
8. Consider postponing bedtime a little until the room is naturally cooler.
9. If you are using air conditioning, make sure you add some humidity back into the environment - with a small humidifier, or water vapour diffuser.
10. Finally remember you child is likely to be thirsty in the night. That usually means more frequent wake-ups and a lot more night feeds. If it's really hot, don't try to restrict these.