> Room temperature is 21°C

Debated, was 23 or 25 in my college textbooks: https://en.wikipedia.org/wiki/Room_temperature

> I have no idea how many freedom fries units that is.

Kind of a bad attempt at humor? Imperial units is fine.

Imperialist here. Freedom fries was funny.

Had to add metric to an imperial unit application since it is to be sold internationally. I live in a Fahrenheit country so I set my phone, computer, and car to Celsius to learn how the the temperatures readings feel.

I 100% agree, "Freedom Fries Units" is quite fitting.

Turns out I prefer Celsius over Fahrenheit in day to day usage.

The US doesn't use Imperial units. It uses US customary units, which are different from Imperial in several significant ways, because the Imperial system evolved after the US split from the British Empire.

Also interestingly, US customary units are defined in terms of metric. So in a sense, the US does use the metric system.

https://en.wikipedia.org/wiki/United_States_customary_units

I often correct people regarding the US not using Imperial as well but to be fair the only significant difference these days is in fluid measurements. Weight and length measurements were standardised between US customary and Imperial back in the 1950s

https://en.m.wikipedia.org/wiki/International_yard_and_pound

That is good to know. Also linked from that article:

https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and...

68.9deg F

A shockingly useful "quick and dirty" estimate for C to F for temps humans are likely to encounter is 2x + 30. It's not precise at all, but for purposes of "what does that feel like outside" or "should I bring a sweater" it works pretty well.

21C would, by this estimate, be 72F. The true conversion is just shy of 70F, so, again, it's not correct but it's close enough for this kind of conversation.

I try to remember: 0 = freezing 10 = chilly 20 = comfy 30 = warm 40 = scorching.

30's hot, 20's pleasing, 10 is not, and 0's freezing.

Also fun:

FAHRENHEIT

  0: Very cold    
  100: Very hot  

CELSIUS

  0: Moderately cold
  100: Dead

KELVIN

  0: Dead
  100: Dead

for what it's worth: add 9 degrees F (or 18 if it's easier to remember) for every 5 degrees C (10 C, easier), and peg 32F to 0C. You get:

-40F=-40C

-22F=-30C

-4F =-20C

14F =-10C

32F = 0C

50F = 10C

68F = 20C

86F = 30C

104F= 40C

and then approximate in between from there. It's quick enough for me now that I skip the 2x+30.

These points make it easy to remember for me, adding ~5C for 10 F.

40 F = 4 C (forty is four)

50 F = 10 C

60 F = 16 C (sixty is sixteen)

In this HN subthread: users slowly converge on the conversion formula for Celsius to Fahrenheit (32+9C/5) in greater and greater precision while calling it an “approximation.”

10c is 50f (easy to remember) 27c is 81f (it's all threes!)

Always interesting what's easier for some people. Personally 9/5x + 32 is much easier for me to remember and calculate

The irony is that (at least I'm pretty sure) the concept of "room temperature" was originally pinned to 70° Freedom Degrees. Your 21°C reference unit is probably a rounded conversion, which explains the sibling comment arguing 23°-25°C as potentially inferior alternatives. An accurate conversion would be 21.1̅°C.

Conceivably, if you had an umbrella to protect yourself from the acid rain, an oxygen mask, and were on a very safe floating platform in the upper atmosphere, you could walk around in a t-shirt and be just fine.

The Fahrenheit scale is European, not American. It was created in Poland well before the United States broke off from Great Britain. We're just slow to change.

Maybe there is a reverse psychological angle to make the current US administration go metric. Fahrenheit->Polish->European->Communist/Woke. Can't have that!

> Maybe there is a reverse psychological angle to make the current US administration go metric. Fahrenheit->Polish->European->Communist/Woke. Can't have that!

1. That nonsensical, because the same logic would apply to Celsius temperatures.

2. Americans don't keep using Fahrenheit because of some aversion to Europe. Though I do have some fondness for it as resistance to the machine-people who are always going on about efficiency and trying to hurry everyone up.