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# UnitTemperature

A unit of measure for temperature.

```
class UnitTemperature
```

## Overview

You typically use instances of [`UnitTemperature`](/documentation/Foundation/UnitTemperature) to represent specific quantities of temperature using the [`NSMeasurement`](/documentation/Foundation/NSMeasurement) class.

### Temperature

Temperature is a comparative measure of thermal energy. The SI unit for temperature is the kelvin (K), which is defined in terms of the triple point of water. Temperature is also commonly measured by degrees of various scales, including Celsius (°C) and Fahrenheit (°F).

The [`UnitTemperature`](/documentation/Foundation/UnitTemperature) class defines its [`baseUnit()`](/documentation/Foundation/Dimension/baseUnit()) to be [`kelvin`](/documentation/Foundation/UnitTemperature/kelvin), and provides the following units, which are initialized using [`UnitConverterLinear`](/documentation/Foundation/UnitConverterLinear) converters with the specified coefficients and constants:

|Name             |Method                                                                            |Symbol|Coefficient       |Constant            |
|-----------------|----------------------------------------------------------------------------------|------|------------------|--------------------|
|Kelvin           |``doc://com.apple.foundation/documentation/Foundation/UnitTemperature/kelvin``    |K     |`1`               |`0`                 |
|Degree Celsius   |``doc://com.apple.foundation/documentation/Foundation/UnitTemperature/celsius``   |°C    |`1.0`             |`273.15`            |
|Degree Fahrenheit|``doc://com.apple.foundation/documentation/Foundation/UnitTemperature/fahrenheit``|°F    |`0.55555555555556`|`255.37222222222427`|

## Topics

### Accessing the Base Unit

[`baseUnit()`](/documentation/Foundation/Dimension/baseUnit())

Returns the base unit.

### Accessing Predefined Units

[`kelvin`](/documentation/Foundation/UnitTemperature/kelvin)

The kelvin unit of temperature.

[`celsius`](/documentation/Foundation/UnitTemperature/celsius)

The degree Celsius unit of temperature.

[`fahrenheit`](/documentation/Foundation/UnitTemperature/fahrenheit)

The degree Fahrenheit unit of temperature.


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