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Comment by gpvos | Hacker News Reader

200F = 93.3C, 190F = 87.8C. Really, we're talking about boiling, why would one even consider using Fahrenheit?

In some places, most of your instruments will likely be in Fahrenheit and Fahrenheit is what you use daily for most tasks. It only makes sense that you use Fahrenheit as your reference point.

A home in other places is more likely to have Celcius, and you'll likely use it.

It isn't like it is difficult to convert.

On the contrary Fahrenheit and Celsius is one of the harder units to convert. Can't just "halve and remove 10%" in your head like you can for pounds. Though I agree with you that you can't expect Americans to use SI units.

Most folks reading this will have the internet. It makes conversion easy. If you don't, charts help get most common things converted.

Easy.

The scale factor is 9/5, which is close enough to 2 that the precision is fine for casual conversion (weather report, discussion of boiling tea on the web, …)

Definitely not. Say, 86F to C. 86F is 30C, but dividing the F by 2 would give you "43C", which converts to 109F. That is not a trivial difference.

You forgot to subtract 32 first. Then you get 27. Or in this case, 54 happens to be evenly divisible by 9, so doing the exact conversion is relatively convenient (divide by nine, multiply by five).

No, it is very hard to convert.

The US has about 4% of the world population. Adapt. It's not worth the communication problems.

i suppose they will when they have to.

They more or less did. It's just the general public that for some reason still uses these units.

No point in using kph for speed if all of the signs are in mph. No point in learning C for air temperature if the forecasts are in F. No point in using metric volume measurements if it doesn't match the measurements on your cooking tools. No point in using metric height and weight at the doctor if the form requests inches and pounds.

And so on. You just don't have a choice unless the government makes the switch mandatory. So you use it as it comes up: Metric for medicine, for example, but not to figure out your clothing for the day.

In Ireland we changed all the road signs to kph 20 years ago. It too some minor adjustments but that was that.

No, it is very hard to convert.

Do you think folks are doing it by hand? nope, they use the internet, the same thing we are communicating on.

I agree that the US should convert, but that's another discussion. No need to crap on folks for using something familiar when we all know that's why they do it.

I used a generic unit conversion app that has a specific function for F-to-C conversion. That takes a minute or so to start, enter the numbers, etc. I could have read tens of paragraphs of text in that time.

I agree I'm being a bit harsh here, coming out of the blue on a random comment. But in general I'm very irritated that using non-metric units in an international forum is still a thing. The onus should be on the Americans in their communication, not on others.

The UK and Canada have converted, or are in transition. It takes a generation or maybe two, but I'm certain it's worth the trouble.

not easy to convert accurately in your head, but google does unit conversion right in the search bar:

  "200 f to c"

and macOS spotlight you can go even shorter:

  "200 f"

USian here, two perspectives. I wish we used the SI system, it’s clearly superior and I agree about the communication problems. It’s also really not that hard to convert temperature roughly, just a factor of two and a constant.

The US customary units have a lot advantages. For example:

In Fahrenheit, 0 is really cold while 100 is really hot. In Celsius, 0 is kind of cold while 100 is damaging to life.

With feet and inches, you can easily divide a foot by 2, 3, 4, and 6 with no repeating decimal digits. It's the same reason the ancient sumerians used base 60 for their number system.

With liquid measure, a cup is roughly what would be considered a serving with a meal while a litre is one hundred millionth the distance from the equator to the north pole, cubed

0 is freezing, 100 is boiling.

12 is a handy number but decimal calculation isn't difficult either, especially when all your units use the same.

What is a cup? How do you do calculations with a third of a cup etc?

I know a cup is roughly 200 mil. From exposure in life I know 200ml is about a cup of tea and 300ml is about a mug of coffee /can of come, 500 is a big can of beer. How many cups are in a can of beer?

A can of beer is 12oz or 16oz.

So you change which unit you're using depending on what you're measuring? Much handier.

>/can of come

You can buy it in cans now?

As a non-American I don't understand the Fahrenheit vs Celsius arguments. What's special about 0F being really cold and 100F feeling really hot? I find that -20C being really cold and 30C really hot quite intuitive and easy to understand. Also in terms of weather it is easy to understand that below zero temps snow and ice will form. Add the convenience that Celsius is basically just an offset of Kelvin and I really don't see the appeal of Fahrenheit at all.

In terms of outdoor air temperature in the North East US, 0-100F is basically the temperature range you’ll experience throughout the year. 50 is about average in spring/fall.

It's just American Exceptionalism. Many people in the US categorically refuse to entertain the idea that their system isn't the best, and come up with justifications that sound funny to outsiders.

I've been living here for 15 years and the recurring pattern still hasn't stopped being funny.

> In Fahrenheit, 0 is really cold while 100 is really hot. In Celsius, 0 is kind of cold while 100 is damaging to life.

0C: I need shoes, pants, sweater, coat, gloves.

10C: sandals, pants, two light layers.

15C: sandals, shorts if sunny, one long sleeved top.

20C: sandals, shorts, shirt. Hoodie if windy.

25C: sandals, shorts, shirt optional.

Etc.

How is F more convenient in any way?

F to C -> subtract 32 and divide by 1.8

C to F -> multiply by 1.8 and add 32

This sounds messy but works out well for a lot of temperatures we are used to, for example... 0C is 32F ... 100C is 212F ... 20C is 68F ... 30C is 86F ... etc.

Why on earth would anybody willingly do that, unless forced by situation... and that situation should not be happening in 2023, period. Heck, even whole science is on metric system and Celzius/Kelvin scale so there goes usability argument.

I've heard all the excuses in past 4 decades whenever this topic comes up, but they can all be summed up as: butthurt ego, we are better than anybody and we don't care about reasons.

In Europe, during more primitive medieval times, even my tiny little country that wasn't country before had maybe 10 different measure systems mostly based on human body, various weight systems etc. There were always reasons for system XYZ, different conversion tables and so on. They were not worse than what US uses now, and are all part of history for same very good reasons.

Its not even a topic about 2 balanced viewpoints like driving left or right, metrics et al have trivial conversions so even folks struggling to finish primary school are well versed in it. What you describe is impossible to do for even older university-educated folks, unless they have been doing it for their whole lives.

I always forget when do subtract or add, or divide or multiply. So I use the known conversions 0->32, 100->212 to help remember.

what's your take on languages

Dude we all have robot calculators in our pockets - it’s the work of seconds to convert with zero thought on the user’s part:

“Hey Siri convert 190°F to Celsius.”

“190°F is 87.77 degrees Celsius.”

Boom. It is not very hard to convert.

The US represents half the readership on this forum. Audience-wise it's a "pick your poison" scenario in avoiding communication problems, so what's wrong with an individual copying their notes into a website not just leaving the units as written?

Unfortunately, a lifetime in the U.S. has left me with poor intuition for Celsius. The conversion isn't difficult to do in ones head and for laboratory work, naturally, it's just as easy to read one thermometer scale as another. For everyday life, weather reports, fever thermometer readings, thermostats and such, it is just a nuisance to convert from Fahrenheit and back. If someone tells me it's 15 degrees C outside I have to do mental arithmetic to know if I should take a sweater. Furthermore, from a purely logical perspective perhaps we should even consider using Kelvin.

It's a completely different story for distance, weight and volume. Metric measurement in these cases are more intuitive for me, and they are clearly superior too. Millimeters are so much easier to use than fractions of an inch (7/32 inch -- that's a ridiculous system). In the U.S., an ounce of flour weighs less than an ounce of gold. Who even knows how much a grain of gunpowder is in units anyone else uses (one grain is approximately 1/16 gram). There are three teaspoons in one tablespoon, but only two cups in a pint, 2 pints in a quart and 4 quarts in a gallon.

I'd be happy to switch from imperial to SI units for length, mass, and volume. I'll gladly switch slugs to kilograms and pounds to Newtons, but I will miss Fahrenheit.

> In the U.S., an ounce of flour weighs less than an ounce of gold.

Wait, what?

I mean: WHAT?!

There's a children's riddle here: "what weighs more: a pound of feathers or a pound of lead."

I hesitate to ask what the US answer to this would be.

Two different units, both called an ounce.

It's the avoirdupois ounce (exactly 28.349523125 g) for everything but precious metals, where the Troy ounce is used (exactly 31.1034768 g).

Once you know 100 is boiling, a simple rhyme helps to remember Celsius for common weather temperatures:

30 is hot.

20 is pleasing.

10 is cold.

And 0 is freezing.

As much as I prefer Celsius and have no idea what temperatures are in Fahrenheit, it seems quite obvious why people will use it - because it’s what one knows and what is used where one live.

Even as an Aussie I have to disagree with you here. The commenter at least put Fahrenheit in the degree.

People are allowed to communicate in a way that they're familiar with. If they have used F their entire life and so has everyone around them, then its fine.

The US demographic represents roughly 41% of Hacker News, I think its fine if they use their own measurement system.

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