v0.31:Temperature

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This article is about an older version of DF.

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
Human Body Temperature	10066.6²	98.6	37.0	310.15	558.27
Freezing Point of Water	10000	32	0	273.15	491.67
Boiling Point of Water	10180	212	100	373.15	671.67
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
fire	11000 U
common stone melts	11500 U
magma	12000 U

Melting point

This is the temperature at which an object will melt.

Boiling point

This is the temperature at which an object will evaporate.

Ignition point

This is the temperature at which an object will catch fire.

Heat damage point

This is the temperature above which an object will begin to take heat damage. Flammable items without a heat damage point (or with an exceptionally high one) will take damage very slowly, causing them to burn for about 9-10 months before disappearing.

Cold damage point

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

Specific heat

This determines how long it takes an object to heat up or cool down. An object with high specific heat will change temperature more slowly.

Fixed temperature

A substance'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 the nether-cap, whose temperature is always at the melting point of water. If a substance's temperature is fixed to between its cold damage point and its heat damage point then items made from that substance will never suffer cold/heat damage, unless it's dumped into magma or water. This makes nether cap fire-safe and magma safe, in spite of being wood.

The fixed temperature of an item is set when the item comes into existence, so you can't change the MAT_FIXED_TEMP token to cause an existing item to melt/burn/etc.

The fixed temperature of a container has no effect on its contents, so you can't freeze water by putting it into a bucket made from nether cap.

The fixed temperature of a substance only affects items made from that substance. For example, setting a type of rock to have a fixed temperature over its melting point won't cause walls made from that rock to instantly melt, cause ice walls adjacent to the rock walls to melt, or even cause them to be considered warm stone.