• Avoid using a Mac on a bed or fabric surface. Anything soft doesn’t allow for sufficient heat dispersion and can even block the air ventilation on many portable Macs, try to always use a Mac on a hard surface of wood, metal, or glass.
• Use a laptop stand. On hot summer days a laptop stand can mean the difference between having the fans blasting or not having them on at all. Anything that raises a Mac away from a base surface allows for heat to radiate out and for air to flow around it, cooling the hardware. Some laptop stands have built-in fans that blow directly onto the underside of a computer, these can be very effective.
• Raise the rear of a MacBook. No laptop stand? Make do with what you have, and try placing the rear of the Mac elevated by a hardcover book or something similar. It’s not as effective as a laptop stand, but this promotes airflow and can make a significant difference in keeping hardware cool.
• Place a Mac at the edge of a table or desk. No stand and no book to raise the computer with? Try hovering the rear end of a MacBook over the edge of a desk or surface to increase air flow where Macs blow out their heat.
• Use a fan. Yes, a standard room fan. This may sound silly but if you’re in an environment without air conditioning, pointing a fan onto a Mac will blow cool air onto it and help disperse heat. If you’re using a Mac in temperatures over 90°F (32°C), this is one of the best things you can do to not only keep yourself cool but also your computer.
• Keep away from the sun. Again this may seem like common sense, but using a computer in direct sunlight places an unnecessary burden on the fans. Even on reasonably mild sunny days the sun can cause fans to go into overdrive, it’s best to avoid direct sunlight completely.
Finally, a quick word of advice: if you’re in extreme heat and you don’t have any method to cool down your Mac, do yourself a favor and don’t use it at all until you get out of the crazy weather. Heat is one of the most detrimental forces to anything electronic and overheating can lead directly to reduced lifespan of hardware, diminished battery capacity, and other problems. It’s always better to be safe than sorry.