Why Does the United States Still Use Fahrenheit?

The United States, along with Micronesia, Palau, the Marshall Islands, the Bahamas, Belize, and the Cayman Islands, are the only countries that still use the Fahrenheit scale for temperature. While the rest of the world had no major problems adopting the Celsius scale and the metric system in general, Fahrenheit remains in use despite its disadvantages. Many wonder why, and proposals to retire Fahrenheit have been several, but like so many other things in life... it's complicated.

Daniel Gabriel Fahrenheit presented his measurement scale in 1724, and almost automatically caused a revolution. History tells us that Fahrenheit based his work on the Rømer degree of 1701, which marks zero at the freezing point of brine. With a more advanced calibration process and adjustments in multiplication, Fahrenheit set the melting-freezing point of water at 32°F, the human body temperature at 96°F (in real life it's a bit higher), and the boiling point of water at 212°F.

In other words, a degree Fahrenheit is 1/180 of the interval between the freezing and boiling points of water. Once we understand its origin and visualize the conversion process to Celsius ((F - 32) / 1.8 = C), Fahrenheit doesn't seem so difficult... but it is. And in the United States they still use it. Why?

The United States and the Fahrenheit Scale

In reality, this extends to the entire 'Imperial System' (a vestige of the British Empire), and its resistance has had serious consequences, such as the loss of the Mars Climate Orbiter in 1999 (Lockheed Martin's software calculated thrust in pound-seconds when Newtons per second were expected), while a report issued by the US Centers for Disease Control and Prevention indicates that between 3,000 and 4,000 children are admitted to hospitals each year due to medication overdoses associated with conversion errors.

Still, there have been several attempts at change. In December 1975, Congress passed the "Metric Conversion Act", which aimed to encourage adoption of the metric system through educational campaigns, but all it achieved was a sign with kilometers on Interstate 19 connecting Arizona with Mexico. The fundamental problem was that the act was voluntary, when in other countries (the United Kingdom, Canada, and Australia, for example) it was made mandatory.

Logically, the public resists drastic changes, though there is another underlying factor: the economic one. The removal of Fahrenheit and the massive (and mandatory) adoption of the metric system will require a lot of money, and there is not yet sufficient evidence to justify the investment. In everyday applications, Fahrenheit seems sufficient, no matter that the annoyance of conversion remains.