I have come up with a new way to think about Fahrenheit and Celsius. Behold, my masterpiece:

Very          Water                              Very
Cold        Freezes               Nice            Hot
-20C             0C                20C            40C
  0F            32F                70F           100F
   |              |                  |              |
   --------------------------------------------------
                      |    |               |
                    40F  50F             82F
                     4C  10C             28C

Read on to learn about how this amazing cultural and scientific product came to be...

Here's a funny and informative graphic that was going around a while ago:

So from here we can see that Fahrenheit is clearly the superior scale for human environments.

But how does someone familiar with Celsius understand what it's like outside based on the Fahrenheit weather, and vice-versa?

This Hank Green tweet proposed a simple way to think about Celsius:

Hey, having a hard time with Celsius? Ignore the second number and it’s basically just how hot it is on a scale of 0 to 5.

Pretty good, but I thought, it could be better. I'd like to have a mental scale that I think of as analogous to 0–100 in F. Let's start with a few facts:

• around 70 F is "nice"
• 70 F is 21 C
• 32 F - water freezes
• 0 C - water freezes
• 0 F is -18 C
• 100 F 38 C

So if we're going for a good enough mental scale, maybe we can say that the range of Celsius aligning with Fahrenheit is about -20–40. There is also the sort-of pattern that frozen water is about a third from the bottom of the range, nice weather is about 2/3 from the bottom.

So we have:

Fahrenheit

• 0 is Very Cold
• 32 is Frozen Water
• 70 is Nice
• 100 is Very Hot

Celsius

• -20 is Very Cold
• 0 is Frozen Water
• 20 is Nice
• 40 is Very Hot

In addition to that, a few other mnemonics/markers:

• 40F is 4.4C
• 50F is 10C (as in 50.0̅ is 10.0̅ which is very shocking to me)
• 82F is 28C