One thing you're going to need in order to survive in a hot-weather desert is water. The intense sunlight and heat you'll endure means you'll be sweating out most of your water. If you don't replace it fast enough, you'll suffer from dehydration. The following are signs that dehydration may be setting in:

Mild dehydration:

Lack of saliva
Decreased frequency and amount of urine
Deep color and strong odor in urine

Moderate dehydration:

Even less urine
Dry mouth and sunken eyes
Rapid heartbeat

Severe dehydration:

No urine
Lethargy and irritability
Vomiting and diarrhea

[source: Mayo Clinic]

The other danger is heat casualty, which we'll go over in detail later on.

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Collecting firewood in the Sahara

One thing that makes it more difficult to lower the body's temperature in the desert is a lack of shade and shelter. This means more heat, more sweat and, you guessed it -- the need for more water. It's generally thought that the human body needs about one gallon of water per day in this harsh environment. How harsh? The record high temperature for Death Valley, California, was 134 degrees Fahrenheit (56.6 Celsius) in July 1913. While this was a one-time reading, the average summer daytime temperature in Death Valley is about 110 degrees F (43.3 C) [source: USGS].

It's a common mistake for someone in a survival situation to try to ration his or her water. People are often found dead with water still in their canteens. Here's a survival axiom that could help save your life: Ration sweat, not water. And don't listen to your thirst meter -- if you only drink when you're thirsty, you'll be getting about two-thirds of the water you need.

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Cottonwood trees in Utah

If you're stranded in the desert without any water, follow these steps:

If you find a trail, follow it. It may lead to civilization.
Look for birds in the morning and evening. They'll often circle over water.
Dig near cottonwoods, willows, sycamores, hackberry and cattails for groundwater.
Cactus fruit bears water -- but be careful, because some are poisonous. If you don't know your desert plants, don't risk it. There isn't a sure-fire indicator.
Breathe through your nose and avoid talking.
If you find wet sand, dig down to get to seeping water.

You can find more tips in How to Find Water in the Wild. That article also details how to build a solar still to acquire water. While that's a good idea in many survival scenarios, it's not wise to do so in the desert. You'll lose too much sweat for the small amount of water you'll be able to collect.

The other thing you'll want in the desert is fire. Even though daytime temps are severe, the desert can get very cool and even cold at night. Aside from providing warmth, fire will also: