14 Jun 2019

Why Does the US Use Farenheit Instead of Celsius?

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Norman Rockwell, 15 Below.


Short answer as to why Americans use Fahrenheit – it’s people who want to know the temperature.

Fahrenheit is how hot it feels to humans.
Celsius is how hot it feels to water.
Kelvin is how hot it feels to atoms.

We’re all atoms, we’re all primarily water, but we are human.

12 Feedbacks on "Why Does the US Use Farenheit Instead of Celsius?"


I heard once that the Fahrenheit scale was named after Daniel Gabriel Fahrenheit and was very confusing. Much better to use centigrade as it was very straightforward and the name reflected the structure of the scale and it didn’t glorify some dead white guy. Then they changed the name to celsius for Anders Celsius, a dead white guy.

I still use centigrade even though I get funny looks when I do.

David Moelling

Almost all US Customary Units (no they are not Imperial Units) have values that are usable. 1 degree F is a small but meaningful change. 1 degree C is too large. Remember that the French revolutionaries wanted a 10 month year with 10 hour days.


The simple reason why we haven’t gone metric is that in the 60’s when we were preparing to make the change and the schools were teaching metric and highway sings were being changed to metric. some businessman was going to lose some profit due to the change. So he bought a US senator (I understand that they can be bought fairly cheaply) who put a amendment on a unassociated bill to “temporarily delay the implementation to metric”. And that temporary delay became permanent. So that is why we measure temp with an F instead of a C.


Nice fantacy “Anon”.

I’d go with “installed base”.

The US has built alot based on certain dimensions & codes. Studs are typically 16 or 24 inches on center. Sheet materials are typically 4 feet wide. The loads & strengths are all in tables that relate to 50 to 100 year old structures. A switch to metric is chaos. for no reason. Most electrical fasteners are #6-32, #8-32, and #10-32. Some “Big Box” Chinese junk has metric internals so none of my taps or drivers work. In the kitchen, “2 medium eggs” and “2 cups” makes sense. X grams egg and Y grams flour (as in the EU) was invented by an idiot who can’t cook.

We used metric in the lab where there is no “historical burden”. Grams, milligrams, micrograms, etc were even of a relevant scale. That isn’t “real world”.

Metric is an obsession for those who only read about work.

Roy Lofquist

The US is the only major nation that does not use metric. It is also the only nation that has put men on the moon.


Mike! I’m guessing you are under age 50. You didn’t see all the highway signs in Kilometers. You didn’t see the push in the schools to teach the kids metric. What I described about the congressman is exactly what happened. We were going metric until the amendment to a bill put a hold on it.

I might add to count me in on those who think we missed the boat on not converting to metric.

Schill McGuffin

I’m 55. I saw the materials in the schools, and I don’t think it was substantially more educational material/time than is used to teach metric measure to kids today, since it really is the standard for the sciences even here in the US. What there _was_ more of back then was a lot more time spent on conversion — teaching

But I also remember annoyance back then at the presumptuousness of it all — and a general attitude that “they can change the road signs and how they measure things in the Army, but damned if I’m gonna start _thinking_ that way.” That they _did_ spend a lot of time teaching conversions back then sort of conceded the point that people were going to be converting between metric and “real” units, rather than just enthusiastically embracing the “progressiveness” it all.

Whatever lobbyists were making payoffs back then, I think there was also a lot of grassroots negativity about the whole matter, that only got stronger as the date approached. I distinctly remember a lot of relief when the postponement happened.

And in the proper American tradition favoring “bottom up” rather than “top down” solutions, those that saw the advantages in metric adopted it, and those not wanting to walk away from their investment in the traditional system,either capital or emotional, ignored it.


MIKE-SMO has got it right. It’s essentially social and technological inertia.

When I was in engineering school, we were taught six or seven different systems of units. All are conventions; none are fundamental.

But, the US is a metric country, and it is one of the chart members of the metric treaty. All of our customary units are defined in terms of their metric equivalent. So, 1 foot is defined to be 30.48 cm, exactly. The pound is officially defined as 453.59237 grams, exactly.

Roy Lofquist

@Robert Sykes

I had one physics prof who had us use the furlong-slug-fortnight system for a couple of weeks. There weren’t any handy conversion tables to be found.


“I might add to count me in on those who think we missed the boat on not converting to metric“

-there’s still time to jump in the lake.


@Roy Lofquist

Well, your professor was just trying to make a point. There is no furlong-slug-fortnight system, and so no one ever had to come up with systems of units.

The ones I was taught are:

pound mass-pound force-foot-second

slug-pound force-foot-second

pound mass-poundal-foot-second


kilogram mass-newton-meter-second

System International

The first system is the current one is use in the US. It is the traditional Imperial System.

It is a gravitational system, so Newton’s Law is written,

F = ma/gc

gc is a constant,

32.17 (lbm ft/sec^2)/(lbm ft/lbf sec^2)

The other systems are all dynamic systems:

F = ma

Some European engineers use a gravitational metric system:

kilogram mass-kilogram force-meter -second



I will note that there are two kinds of countries in the world – those who use metric and those who have put a man on the Moon. That being said, I’m comfortable with metric – it’s like being bilingual. I read once that the French government sent President Jefferson a set of metric measurements, but that the messenger was on a ship taken by pirates and the chance was missed to switch to metric. Jefferson would probably have loved it.


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