Hiking in 100 degree heat with the sun pounding on you is hard, and everything you do in that heat is harder than normal. You have to be prepared for those extreme conditions, because extreme conditions can produce extreme consequences. Here are my top 10 tips to ensure your desert hiking will be as safe and fun as possible.
1) Acclimatize - The more you hike in the desert, the better you handle the heat. My first couple desert hikes left me feeling sick and demoralized. If you plan on backpacking in the desert or doing any serious day-hiking (like hiking to the Colorado River and back in one day in the Grand Canyon) I would recommend plenty of desert day-hiking beforehand. Start small.
2) Temper Your Ambitions - Like I mentioned above, everything is harder in the heat. Expect routine distances and climbs to push your limits. What you can easily accomplish physically in milder climates will be a challenge in the desert. You'll need to be in better shape than what you're used to.
3) Carry a Backpack - One of the strangest sights I see in the desert are people without backpacks... And I see it all the time. If you're not carrying a backpack then you are not carrying the essential supplies needed to safely traverse the desert. The problem is that nobody thinks anything bad will happen to them, but bad happens all the time. You gamble with your life every time you go out without gear. Around the United States, unprepared hikers are constantly being rescued from avoidable survival scenarios that are usually preventable by bringing some common-sense items. You need a backpack to carry those items! You need a backpack to carry water, which is muy importante in the desert. Check out The Mountaineers list of 10 Essentials for what else to carry in your backpack.
4) Bring More Water - Unless you've hiked in the desert in summer, it may be hard to imagine just how much you can sweat, and how thirsty you constantly feel. I've found that bringing double the water I normally bring is just enough. Last Saturday I finished 4 liters on a 7 mile hike. Trust me, you'll need to drink much more water than normal. In the Grand Canyon we started off 3 out of 5 days with 2 gallons of water each, and we drank it all by the end of those 10 mile days. Also, keep in mind that water is really going to dictate where and how far you hike. If you bring 4 liters and notice that you've finished 2 already, then its time to turn around and head back to the car. The bottom line is that venturing out into the desert with an inadequate water supply can easily lead to an evac by search & rescue, and even death. Be prepared.
5) Wear Proper Footwear - Hiking in the desert isn't a walk in the park. The ground can be jagged rocks for miles on-end. Or it can be loose rock and sand that can slip tread and sprain ankles. Furthermore, any variety of cacti will poke the hell out of you at every opportunity. Wearing sandals in the desert is inviting pain and courting death. Wear shoes that will protect your feet from the flora and won't disintegrate from the sharp rocks. If you wear running shoes, consider gaiters to prevent debris from getting into the shoe. Finally, if you're going on a long trip, make sure your shoes are up to the task. The last thing you want is for your shoe to fall apart in the middle of the desert, I've seen it happen.
6) Seek Shade - Heat stroke is a serious risk, and keeping your body from overheating is going to take effort on your part. If you come across shade, take your pack off and sit in it for a few minutes. Drink some water. Let your heart slow down. Let your body cool a little bit. I usually plan my breaks around shade instead of distances. I'll say to myself, "The next shade I come to, I'll take a short break". Trust me, it really helps taking a break in shade versus taking a break in the sun, which can be totally miserable and can sap your energy even further.
7) Sun Protection - This one seems like a no-brainer. Keep sunscreen in your pack. Wear a hat to keep the sun off your face. Wear a wide-brimmed hat or drape a bandanna from the back of your hat to protect your neck. A buff works great at protecting the back of the neck and your ears. Another good idea is sun protective clothing. The Columbia Silver Ridge or REI Sahara line of hiking clothing offer sun protecting, moisture wicking clothing that are great for the desert. Wear polarized sunglasses. I have forgotten sun screen multiple times, and got burned for my stupidity. Now I keep a tube in my day-pack at all times.
8) Keep Track of the Forecast -. I like to use 100 degrees as a good mark of when to start and when to stop. If it's 100 in the morning when I plan to start then I stay home, because it will only get hotter. If it's 100 in late afternoon when I plan to start, then I'll go, because it will only get cooler. Hiking in 110-120 degree weather is too dangerous, and I wouldn't recommend it to anyone, but 100 is doable as long as it's the peak temperature. You can beat the hottest times of the day by hiking near dusk and dawn. Just remember, your tolerance for the heat will be different than mine, so knowing what temperatures you are comfortable with will be key for planning trips.
9) Electrolyte Replacement - I learned this lesson the hard way. For most climates, eating salty snacks like trail-mix and GORP is enough to replenish electrolytes lost during the physical activity of hiking. Since the amount you sweat significantly increases in the desert, supplementing your snacks with an electrolyte replacement can be vital, especially on rigorous days. Besides a whole mess of symptoms ranging from vomiting and dizziness to diarrhea and muscle cramping, electrolyte imbalance can lead to death. Check out brands like Nuun and Hammer that make tablets that easily dissolve in water.
10) Respect and Common Sense - Nothing is a substitute for common sense. Remember that playing in extreme environments can produce extreme consequences. Trust your gut and respect the land. You can't beat the desert, but you can travel through it by foot safely and comfortably if you use your brain. If you're out of water and come across a puddle: better fill up. If you are confused about the best way forward: turn around. If you start feeling weak or dizzy: take a break in some shade and drink water. If you see a sign at the trailhead warning you not to do something: don't do it. You aren't Cody Lundine and this isn't a movie. If you don't respect the desert it will punish you unmercifully.