Celsius vs Fahrenheit Use Around The World

The map above shows which countries use Celsius for measuring outdoor temperatures and which still use Fahrenheit.

According to World Population Review the following 19 countries use Fahrenheit (often in conjunction with Celsius):

Fahrenheit Exclusively:

1. United States
2. Liberia
3. Marshall Islands
4. United States Virgin Islands
5. Micronesia
6. Cayman Islands

Fahrenheit Alongside Celsius:

1. Puerto Rico
2. Cyprus
3. Belize
4. Bahamas
5. Guam
6. Antigua and Barbuda
7. Saint Kitts and Nevis
8. Turks and Caicos Islands
9. American Samoa
10. Northern Mariana Islands
11. British Virgin Islands
12. Palau
13. Montserrat

It’s also used in Canada only for cooking.

And in the UK (as the map above shows) it’s only used by the tabloids when it gets “hot”, as 77°F sounds a lot warmer than 25°C.

Where does Fahrenheit come from?

Daniel Gabriel Fahrenheit (1686–1736) was born in Gdańsk (Danzig), Poland when it was part of Polish–Lithuanian Commonwealth, although he came from a wealthy merchant family of German origin.

His Path to Science and Invention

• Originally, Fahrenheit was trained as a merchant (following in his father’s footsteps), but he was much more interested in science and precision instruments.
• He settled in the Netherlands, which at the time was a hub for scientific progress.
• He became skilled as an instrument maker, producing thermometers, barometers, and other scientific devices.

Development of the Fahrenheit Scale

• Around 1714, Fahrenheit developed the mercury-in-glass thermometer, which was more accurate and reliable than the alcohol-based thermometers used at the time. Mercury’s consistency over a wide range of temperatures made it perfect for precise measurements.

How He Created the Scale:

The Fahrenheit scale is kind of quirky but clever!

Here’s how he set the points:

1. 0°F: The temperature of a mixture of ice, water, and salt (brine). Basically the lowest temperature he could reliably reproduce in the lab.
2. 32°F: The freezing point of pure water.
3. 96°F: Originally, human body temperature (later revised to 98.6°F due to better measurement).
4. 212°F: Boiling point of water at sea level.

Fahrenheit chose 180 degrees between the freezing and boiling points of water, which allowed for more precise subdivisions than the Celsius scale at the time.

Later Life and Death

• He became a member of the Royal Society of London in 1724, one of the highest honors for a scientist.
• Died: September 16, 1736, in The Hague, Netherlands.

Why Fahrenheit’s Scale Was So Successful

 Better Thermometers = More Trust

• Fahrenheit’s mercury thermometers were way more accurate and stable than the earlier alcohol-based ones.
• Alcohol expands inconsistently, and its volume changes depending on atmospheric pressure. Mercury, on the other hand, is much more stable across a wide temperature range.
• Because his thermometers worked so well, people trusted the scale that came with them.

In other words: It wasn’t just the scale that succeeded , it was the whole package of a reliable instrument with a clear, repeatable scale.

Practical, Everyday Usefulness

• The Fahrenheit scale avoided negative numbers in most everyday weather situations (at least in Europe).
• 0°F was colder than most people would experience naturally, so day-to-day weather readings usually stayed positive, which made the readings more user-friendly.
• Body temperature at 96°F (later corrected to 98.6°F) was a nice, easy-to-remember number for health measurements.

Fine Resolution

• Fahrenheit chose 180 degrees between freezing and boiling. That gave finer gradations between temperatures than Celsius (which has 100 degrees between freezing and boiling).
• This was helpful before modern digital thermometers, people could easily read small changes on an analog scale.

 Early Adoption in English-Speaking Countries

• Because Fahrenheit spent time in the Netherlands and England, where his instruments spread quickly, the scale became entrenched in British scientific circles.
• When Britain and later the U.S. standardized measurements, they leaned on what was already in use and Fahrenheit’s thermometers were common.
• The U.S. stuck with Fahrenheit even as Europe slowly shifted toward Celsius.

 Inertia and Familiarity

• Once a system is in place and people are used to it (especially in medicine, meteorology, and daily life), it’s hard to switch.
• Even though Celsius is mathematically simpler, Fahrenheit was already “baked into” many aspects of British and American life.

Why has the US never switched away from Fahrenheit?

 The System Was Already Deeply Embedded

• By the time Celsius (and the metric system) started gaining traction in Europe during the 19th century, the U.S. had already been using Fahrenheit and Imperial measurements for everything, trade, weather reporting, engineering, and everyday life.
• Changing all the infrastructure, machinery, road signs, school materials, recipes… it would have been a massive (and expensive) project.

 Cultural Identity and Resistance to Change

• There was (and still is) a sense in the U.S. of wanting to do things differently from Europe, kind of a post-colonial independence thing.
• Switching to the “European system” didn’t have much political appeal. The public didn’t demand it, and there was no strong push from leaders to make it happen.

 Industry and Economics

• The U.S. became a major industrial power during the 19th and early 20th centuries, before the metric system really took hold globally.
• Manufacturing tools, car parts, machinery, all based on inches, feet, and Fahrenheit.
• Redesigning everything for metric? Super costly.
• Even today, the aerospace and construction industries in the U.S. still rely heavily on Imperial units.

 Half-Hearted Attempts at Switching

• The U.S. actually passed the Metric Conversion Act in 1975, but here’s the key word: it was voluntary.
• The law encouraged industries to move toward metric, but there were no penalties for staying Imperial, so… most people ignored it.
• Some industries (like science, medicine, and the military) do use metric consistently, but the general public does not.

 People Are Used to What They Know

• Fahrenheit feels more “intuitive” to many Americans for weather:
  • 0°F = very cold
  • 100°F = very hot
• Compare that to Celsius, where typical temperatures hover around single digits or teens, which can feel less natural to people who grew up with Fahrenheit.

Example: Saying “It’s 72 degrees outside” (nice and comfy) sounds very different from “It’s 22 degrees outside” if you’re not used to Celsius!

 The Metric System Was Political, Too

• The French Revolution played a big role in developing and spreading the metric system.
• Some countries resisted partly because metric was seen as tied to revolutionary France.
• The British Empire and its former colonies (including the U.S.) were slower to adopt because they had their own established systems.

Which is Better Celsius or Fahrenheit?

Celsius: The Scientist’s Favorite

Pros:

• Directly tied to water: 0°C is the freezing point, 100°C is boiling (at sea level). Super logical, super clean.
• Makes calculations easy in science, chemistry, and physics, where water’s behavior is important.
• Works smoothly with the metric system (grams, liters, meters, etc.).
• Used by most of the world (except the U.S., a few Caribbean countries, and Liberia).

Cons:

• The numbers can feel too compressed for daily weather:
  • “It’s 1°C” vs. “It’s 34°F” Fahrenheit gives more “room” between temps.
• “Comfortable” human body temperatures are in the 30s and 40s on the Celsius scale, which can feel less intuitive to some.

Fahrenheit: The People’s Weather Scale (well… in the U.S.)

Pros:

• More precise for daily life: there are 180 degrees between freezing and boiling, compared to 100 in Celsius, so you can describe smaller temperature changes without decimals.
• Human comfort range feels natural:
  • 0°F = really cold
  • 70s°F = comfortable
  • 90s–100°F = hot
• Better for weather forecasts, cooking, and general life stuff (if you’re used to it).

Cons:

• Not tied to scientific constants (it’s based on brine freezing and a bunch of historical quirks).
• Almost no one outside the U.S. uses it, so if you travel or work internationally, it can be confusing.
• Scientists and medical professionals still mostly prefer Celsius (or Kelvin).

What Scientists Use:

• Celsius (or Kelvin for absolute temperatures) is the go-to for science, medicine, and engineering.
• Fahrenheit is almost never used in scientific work because it’s not based on universal reference points.

Which one do you think is better?