The following rules expand on the default rules for Hazards in the default Savage Worlds rules

Temperature

Heat

The key to surviving the scorching heat of the desert is to drink plenty of water, carry a light load, and limit one’s exertions to a bare minimum during the hottest part of the day. The Water column lists the daily amount of water character must drink to mitigate the effects of Heat. Without enough water a character’s ability to resist Heat is weakened, and after 24 hours they must start to make Vigor checks against dehydration as per the Thirst rules.

When the temperature reaches 90 degrees or more, heroes must make Vigor rolls every four hours. Those who fail take Fatigue that can only be recovered by cooling down (see Recovery, below). 

Modifiers: Subtract 1 or 2 from rolls if the characters engage in vigorous or extreme activity. Impose an additional penalty based on the severity of the temperature, as indicated by the table. The temperature penalty is doubled if the character does not have enough water.

Heatstroke: If a character is Incapacitated from heat he must make another Vigor roll. Success follows the usual rules for Incapacitation from Fatigue, but failure permanently reduces his Vigor a die type (to a minimum of d4). A Critical Failure on this roll means he perishes. 

Recovery: A victim must cool down somehow to recover Fatigue. This usually means water, shade, air conditioning, etc.

Night Time

At night, the temperature in the desert drops rapidly. Reduce it by 1d2+3 levels (min. Frigid). Even in high summer, the temperature in some areas regularly drops below freezing, allowing frost to form. The seven cities and their immediate vicinities are protected by the Sorcerer-King’s magic, so these temperate zones only drops by 1d2 levels.

Cold

While the scorching deserts can be dangerous during the day, travelers must still be wary of biting, bitter winds at night. For every four hours spent in weather below freezing (32° F), a character must make a Vigor roll. Failure means he gains a Fatigue level. Subtract 2 from the victim’s Vigor roll for every 20 degrees below freezing, to a maximum of −4. 

Clothing: Subtract 2 if the character has only light clothing. Proper gear can mitigate these risks and provide a bonus.

Death: Incapacitated victims die after 2d6 hours instead of waking Exhausted. 

Recovery: Victims can only recover Fatigue once they receive adequate warmth and shelter.

Shelter

Whether it is a cave, a house, a tent, or a refuge spell, shelter provides protection from the sun and desiccating winds. Shelter lowers the temperature by one to four levels, depending on how windproof and covered it is (min. Temperate). With a suitable fire, the temperature inside a sealed shelter at night rises to a comfortable level.

Food and Water

Hunger

Average-size humans need about 1,500 calories of reasonably nutritious food per day to avoid the effects of hunger. If sufficient sustenance isn’t available, a character begins to suffer from hunger. 

After 24 hours without enough food, the victim must make a Vigor roll. Subtract 1 if the individual has less than half the required calories, and −2 if he has no food at all. Failure means the character gains a Fatigue level. 

Death: An Incapacitated character dies from hunger 3d6 hours later. 

Recovery: The victim must have at least a half day’s food to recover

Thirst

An average-sized human requires two quarts of water a day. This requirement is modified by high temperatures, as listed on the table.

If enough water isn’t available, the hero begins to suffer from dehydration. A day after he can’t get enough water, he must make a Vigor roll every eight hours (every four hours in a very hot or hotter environment). Subtract 2 if he has less than half the water he needs in that period, and −4 if he has no water at all. Failure incurs a level of Fatigue and Critical Failure means he’s Exhausted. 

Recovery: Characters recover Fatigue levels normally after receiving sufficient water. 

Death: An individual Incapacitated by thirst perishes after 2d6 hours

Size

When it comes to water consumption, size matters. In most cases, animals and monsters get water from devouring their prey, rather than lapping it out of oases. Ignore them for the sake of fast play. Only horses and camels are important because of their use as mounts. 

A Small character (such as a halfling) requires half the listed water per day. An Obese character increases the amount of daily water he must consume by +1 quart. This modifiers are applied before the benefits of any Edges (racial or otherwise). 

Riding horses require +4 quarts a day, and war horses require +6 quarts. Camels typically require the same quantity of water as a Size 0 creature, but can go for long periods without water, consuming vast quantities when water becomes available.

Finding Food and Water

As can be expected, survival isn’t easy in the deserts of Athas. While the same standards of supplying for yourself on a success and for up to five people on a raise still apply, the harshness of the terrain can impose a penalty. Fertile Regions can give up to +2 to this check.

Sleep

Most people need a minimum of six hours’ sleep out of every 24. A character who goes without must make a Vigor roll at a cumulative −2 every 24 hours thereafter (to a maximum penalty of −4) or suffer Fatigue.