Deserts might be the most inhospitable climates that exist in any world, yet some cultures flourish in or near these environments. In a traditional D&D overland expedition the environment is reflective of the temperate zones of Europe, and thus many of the overland rules assume this kind of a climate. Adjustments, like in life, will be needed when basing a game/campaign in a desert location. Water, beasts of burden, armor, and many other items will have to be taken into account so the setting seems real.
|Possibly the harshest environment that the characters can enter.
Navigation in the desert is extremely difficult, one sand dune tends to look a lot like another. PCs that are not familiar with the terrain, or traveling without a guide will need to roll once per day and on a 1-3 on a d6 they become lost. If your system uses Rangers, and their native terrain is not dessert, the roll becomes 1-2 on a d6. Traveling by night, without an experienced guide, will increase the chance of getting lost to 1-4 on d6. The DM can determine were the characters end up, or a simple random roll. Needless to say, this diversion from their intended will cost the players in supplies, and could lead to starvation, dehydration, or running into a monster.
|You need the right tools for the climate.
If a character does not receive their full allotment of water in a day will start suffering the effects of dehydration. A character that does not receive at least half the amount of water needed in a day will suffer d6 CON loss. A character that does receive at least half the needed water or more in a day(but not a full amount) will suffer a d4 CON loss. This loss in CON comes with all the appropriate effects of any change in CON, including the lowering of a character’s HP. Once a character gets a full allotment of water for the day, the CON loss is restored. If a character reaches zero CON, the character has died due to dehydration. Every day beyond the first that a character does not get at least half the amount of water needed, that character suffers a cumulative -1 penalty to attack and damage rolls do to the weaken state.
Heat is a major factor in the hot winds of the desert and people need to dress appropriately or suffer the effect of heat exhaustion. Character that wear heavier armors will have penalties to combat due to the extreme temperatures. Characters that are wearing chainmail armor will have a -2, and those with plate mail -4 penalty to all attack rolls. They will also suffer a respective +2 and +4 penalty to attribute checks. Shields that are not specifically designed for the climate will also impose a further -1 penalty to attack rolls and +1 to attribute checks.
|Dress for success in the desert.
The winds and sands can become the enemy of the characters because sand storms are one of the most feared natural phenomenon. The first thing that characters need is to find some form of shelter. Large rocks, clay huts, or even climbing into the guts of a beast can provide the necessary shelter from the storm. Each round that a character is not in a shelter and caught in a storm, they will suffer one point of damage. Characters without some form of protection in the storm will also need to make a saving thrown versus Breath Weapon, or be blinded for 1d6 rounds. If the storm goes on long enough a character can be buried beneath the dunes. The DM needs to determine how deep the character is buried. If you want to randomize roll d10 and that is the depth in feet. Each round the character is buried they need to make a STR and CON check. If the character passes the STR check they can dig 1 foot towards the surface. Characters can also attempt to close the distance from the top by digging down with a STR check. If the character fails the CON check they will suffer 1d4 CON damage as they begin suffocating and getting sand into their lungs. Characters that lose all their CON, will parish. CON will be healed after one turn or rest on the surface. This system is also used in the case of a sand avalanche that ends up burying the characters.