Celcius to Fahrenheit

It was April 15th of back-in-the-day and I was pedaling to work just after 6 am.  The temperature read 28* on the weather channel that morning but it didn't register that 28 on the Fahrenheit scale was below the freezing point of water.

I rolled through a slow corner and was forced through a wide, shallow puddle.  Only it wasn't a puddle and I found myself sideways on a slab of ice still attached to the pedals and holding the bar.

As I extricated myself from the bike, I felt my hip bruising up and I knew my shoulder wasn't doing well either.  It was on that day that I finally understood the real advantage of the Celcius scale.  Not only are there 100 even divisions between the freezing and boiling points of water, but it tells me honestly when the puddle will be a sheet of ice.

So I decided to switch to the Centigrade scale and I've been using it for a while.  When I tell stories to family in Canada and Paraguay, I use Celcius.  Stories to Americans require Fahrenheit.

So I had to learn to convert from one to the other.  Quickly.  The basis of the scale is that 10 degrees Celcius = 18 degrees Fahrenheit.  Here's the scale pattern as it resides in my skull:

Celcuis       Fahrenheit

   40                 104

   30                  86

   20                  68
   10                  50
    0                   32
  -10                 14

I combine that scale with 5*C = 9*F and 37* Celcius is body temperature.  It's all I need for quick conversions and story telling.  Now I only crash on ice when I ignore the shiny part of the road.