Unforgiven Sun

Unforgiven Sun adds a temperature and thirst survival system to Minecraft, making hot environments much more dangerous. Prepare for your journeys, manage your body temperature, and make sure you always have enough drinking water with you.

The mod is also a great challenge for players who enjoy Infinite Desert worlds, turning the endless desert into a true survival experience.

Temperature System

Your body temperature increases in the following biomes:

Desert
Savanna
Savanna Plateau
Windswept Savanna
Badlands
Wooded Badlands
Eroded Badlands

Your temperature only increases if:

It is daytime.
You can see the sky.
You are not standing in water.
It is not raining.
You are not inside a bubble column.

The speed at which your temperature rises depends on several factors.

Sprinting increases heat faster.
Wearing the Nomad Clothing set slows down the heat gain.
Standing near burning Furnaces, Blast Furnaces, Smokers, Campfires, Lava or Fire increases your temperature even faster, as long as you are not cooled by water, rain or bubble columns.

The Nether

The Nether is extremely hot.

While you are in the Nether, your temperature is permanently locked at the maximum value and cannot be reduced. Bring enough drinking water before entering.

Nomad Clothing

The mod adds a new armor set called Nomad Clothing.

It is crafted from Nomad Fabric.

Nomad Fabric is made from:

Leather
Rabbit Hide
Carpet

The Nomad Clothing slows down the rate at which your body heats up.

Your temperature will slowly decrease when:

It is nighttime.
You cannot see the sky.
You are standing in water.
It is raining.
You are inside a bubble column.

Thirst System

Your character now has a thirst bar.

The higher your body temperature is, the faster your thirst decreases.

If your thirst reaches 0, you will continuously take damage until you eventually die of dehydration.

Waterskin

Craft a Waterskin to carry water with you on long journeys.

A full Waterskin contains 8 drinks before it becomes empty.

You can fill it with water from rivers, lakes and other water sources.

You can also drink directly from water sources with an empty hand. The Waterskin is simply the portable solution for traveling.

Dirty and Clean Water

A filled Waterskin can be boiled in a Furnace to produce clean drinking water.

Dirty Water

Restores less thirst.
Applies negative status effects.

Clean Water

Restores more thirst.
Grants a short Regeneration effect.

Recommended Mods

I highly recommend installing Just Enough Items (JEI) to easily view all crafting recipes.

JEI

Link: https://www.curseforge.com/minecraft/mc-mods/jei

I also recommend Flowing Fluids if you want an even more challenging survival experience. Without infinite water sources, water management becomes much more important.

Flowing Fluids

Link: https://www.curseforge.com/minecraft/mc-mods/flowing-fluids

Features

Temperature survival system
Thirst survival system
Portable Waterskin with 8 uses
Boil water in a Furnace
Dirty and clean drinking water
Nomad Clothing to survive hot climates
Dangerous desert survival
Permanent extreme heat in the Nether
Great challenge for Infinite Desert worlds