https://doi.org/10.1351/goldbook.D01562
Non-SI unit of Fahrenheit temperature, \(^{\unicode{x26ac}}\text{F} = \frac{5}{9}\ \text{K}\). The Fahrenheit temperature is related to the Celsius temperature by \(\frac{\theta_{\text{F}}}{^{\,\unicode{x26ac}} \text{F}} = \frac{9}{5}\ \frac{\theta}{^{\,\unicode{x26ac}} \text{C}}\,+\,32\).
Source:
Green Book, 2nd ed., p. 113 [Terms] [Book]