# v0.31:Temperature

For temperature as it relates to choosing an embarkation site, see Climate.

## Temperature scale

Dwarf Fortress uses its own temperature scale in most cases, often called "Degrees Urist" on this wiki. So if you see something like [HOMEOTHERM:10067], don't be amazed.

Magma's temperature is 12,000° Urist.

The highest possible temperature in Dwarf Fortress is 60,000°U - the temperature 60,001°U is used internally for temperatures which have been set to "NONE".

### Conversion

[DF scale] = [FAHRENHEIT] + 9968

[DF scale] = [CELSIUS] * 9/5 + 10000

[DF scale] = [KELVIN] * 9/5 + 9508.33

[DF scale] = [RANKINE] + 9508.33

(Note: Mod-makers may find this Temperature Conversion Utility handy if they find themselves having to convert a lot of temperatures to and/or from Degrees Urist.)

### Reference Chart

Significance DF Scale Fahrenheit Celsius Kelvin Rankine
Boiling Point of Water 10180 212 100 373.15 671.67
Human Body Temperature 10066.62 98.6 37.0 310.15 558.27
Freezing Point of Water 10000 32 0 273.15 491.67
Absolute Zero 9508.332 -459.67 −273.15 0 0
DF Scale's Zero1 0 -9968 -5555.555... -5282.40555... -9508.33

1 - Yes, temperatures in Dwarf Fortress can go far, far below absolute zero, which is physically impossible. Considering Dwarf Fortress also allows perpetual motion, it's best not to ask questions.
2 - Technically, fractional/decimal temperatures are not possible in Dwarf Fortress, as they are stored as unsigned 16-bit integers. For instance, body temp for humans in the raws is rounded to 10067.

Some general information about temperatures in DF (copied from somewhere on the forums):

Event / location Temperature
alcohol freezes 9850 U
water freezes 10000 U
underground 10015 U
outside (varies) 10048 U
dwarf/human body temp 10067 U
floor above magma 10075 U
fat melts 10078 U
water boils 10180 U
material is fire-safe 11000 U
common stone melts 11500 U
burning coal (max) 11640 U
magma 12000 U
titan/forgotten beast fire 14000 U
dragon fire 50000 U

## Melting point

This is the temperature at which the material will melt.

## Boiling point

This is the temperature at which the material will evaporate.

## Ignition point

This is the temperature at which the material will catch fire.

## Heat damage point

This is the temperature above which the material will begin to take heat damage. Burning items without a heat damage point (or with an exceptionally high one) will take damage very slowly, causing them to burn for a very long time (9 months and 16.8 days) before disappearing.

## Cold damage point

This is the temperature below which the material will begin to take frost damage.

## Specific heat

This determines how long it takes the material to heat up or cool down. A material with a high specific heat capacity will change temperature more slowly.

## Fixed temperature

A material's temperature can be forced to always be a certain value via the MAT_FIXED_TEMP material definition token. The only standard material which uses this is nether-cap wood, whose temperature is always at the melting point of water. If a material's temperature is fixed to between its cold damage point and its heat damage point, then items made from that material will never suffer cold/heat damage. This makes nether-caps fire-safe and magma-safe despite being a type of wood.

Due to the way fixed temperature is handled, giving a material a fixed temperature will not cause its actual temperature to change accordingly - instead, its temperature will simply be permanently locked at whatever it was previously. Removing a material's fixed temperature, however, will cause all items made of it to heat or cool until reaching equilibrium with their surroundings.

The fixed temperature of a container does affect its contents, but you can't freeze water by putting it into a bucket made from nether-cap because water will not freeze until it cools below 10000 °U .

The fixed temperature of an inorganic material has no effect on unmined walls made from that material, though boulders will take on that temperature as they are produced via mining.