Why do Americans use Fahrenheit instead of Celsius?

The Fahrenheit scale was created by German scientist Daniel Gabriel Fahrenheit in 1724. In 1742, a Swedish astronomer named Andres Celsius proposed a more user-friendly temperature measurement system based on multiples of 10. Today, the Celsius scale is widely accepted in most countries around the world.

If the temperature this afternoon is 21 degrees, most people would assume it is a beautiful, warm and pleasant day, but on the American scale, 21 degrees represents a very cold winter day.

This is because most countries in the world use the Celsius temperature scale , part of the metric system , which defines the freezing and boiling points of water as 0 degrees and 100 degrees, respectively. However, in the United States and some other territories such as the Cayman Islands, Bahamas, Belize, and Palau, the commonly used temperature scale is the Fahrenheit scale. According to this system, water freezes at 32 degrees and boils at 212 degrees. Thus, 21 degrees Celsius is equivalent to 70 degrees Fahrenheit.

Americans do not like the metric system of measurement.

The persistence of the Fahrenheit scale is one of those puzzling American idiosyncrasies that Americans have, like the fact that Americans call soccer "soccer" instead of "football" like other English-speaking countries. So why does the United States use a different temperature scale? And why doesn't it align with the rest of the world? There seems to be no other explanation for this than stagnant conservatism. Americans don't like the metric system. A 2015 poll found that just 21 percent of the public supports switching to metric units, with 64 percent opposed.

It would make more sense if Fahrenheit were obsolete and Celsius an upstart, but in fact the two scales were created just two decades apart. Fahrenheit is named after the German scientist Daniel Gabriel Fahrenheit , who in the early 1700s was the first to design a mercury-alcohol thermometer that was extremely accurate and consistent. At the same time and place, two thermometers would give the same temperature reading. "It was Fahrenheit's great mechanical skill in working with glass that enabled him to accomplish this," author Henry Carrington Bolton explained in his 1900 book The Evolution of the Thermometer, 1592 to 1743 .

The Birth of the Fahrenheit Scale

When Fahrenheit started, he was primarily interested in getting consistent temperature readings all the time, not comparing temperatures of different things or at different times of day. But when he presented a paper on the system of temperature measurement to the Royal Society of London in 1724, he realized that a standard temperature scale was needed.

'Basically, the Fahrenheit scale was originally created with zero as the coldest temperature of a mixture of ice and salt water, and most importantly, the normal body temperature (about 96 degrees Fahrenheit) created a scale where every number was divisible by 2,' explains Don Hillger, a meteorologist at Colorado State University 's Cooperative Institute for Atmospheric Research and president of the US Metric Association, a nonprofit organization that advocates for the metric system. 'This resulted in a freezing point of 32 degrees Fahrenheit. The boiling point of water was then set at 212. The difference between these two points, again, is a multiple of 2.'

About the Celsius scale

This system seems to have been favored by the former British imperial administration; although in Britain Fahrenheit had been used as the standard temperature scale before, the United States, then a British colony, also used this system.

In 1742, a Swedish astronomer named Anders Celsius invented a simpler temperature system based on multiples of 10, in which the difference between the freezing and boiling points at sea level is 100 degrees. (According to ThoughtCo.com, Celsius originally set the freezing point at 100 and the boiling point at 0, but people eventually reversed the numbers.)

It was not until 1961 that the British National Meteorological Office switched to using the Celsius scale.

The 100-degree roundness of the Celsius scale makes it a natural fit for the metric system, which was officially adopted and developed by the French in the late 1700s. However, English-speaking countries still preferred to use the earlier units of measurement, such as pounds, inches, and Fahrenheit. It was not until 1961 that the UK Met Office agreed to switch to Celsius to describe temperatures in weather forecasts, in order to harmonize its units of measurement with other European countries. Most countries quickly followed suit—with the notable exception of the United States, where the National Weather Service (NWS) continues to publish temperature data in Fahrenheit—even though its staff had long since switched to Celsius.

'The NWS serves the public with reports in Fahrenheit, but much of their operations, such as forecast models, use Celsius ,' Hillger said. 'For most automated weather observations, temperatures are also recorded in Celsius. If the units used in weather reports were converted, the Fahrenheit addition could be eliminated when published to the public. However, even if the NWS were aware of the appropriateness of Celsius, television weather programs are serving an audience that rarely uses Celsius, except for residents of some border regions of Canada and Mexico.'

Jay Hendricks, who directs the Thermodynamic Metrology Group at the National Institute of Standards and Technology (NIST) , points out that the Fahrenheit scale also has certain advantages: "It has a wider range of common ambient temperatures. That is, it can help us feel temperature differences more clearly, for example, comparing 70 degrees F and 71 degrees F, is more detailed than comparing 21 degrees C and 22 degrees C. Because humans can distinguish down to 1 degree F, this scale gives a more accurate feel to the human experience."

But the advantage of the Fahrenheit scale is lost when using decimals to represent temperatures in Celsius. "For example, the equivalent of 70 and 71 degrees Fahrenheit, when converted to Celsius, would be 21.1 and 21.7 degrees Celsius," Hendricks adds.

Interesting side information

According to the National High Magnetic Field Laboratory , Anders Celsius, the creator of the Celsius scale, was also the first to discover the connection between the aurora borealis (or northern lights) and fluctuations in the Earth's magnetic field in 1733.