Centigrad to Fahrenheit made easy

[757guy]

I convert C to F all the time from hourly aviation reports.

C temp X 2 - 10% + Add 32 = F temp

Example:

19C X 2 = 38 - 10% (3.8) = 34.2 + 32 = 66.2F

 

[Silk]

Originally Posted By: HerrStig
except that the scale has fewer divisions


Metric uses a decimal point. Not relevant in the real world. I ride a motorcycle to work, the weather forecast is an important part of my day - if it's 7C or below I'll need some extra protection. I don't care if it's 7.9 or 7.1, seeing the 7C is the figure I need to see.

 

[hotwheels]

Originally Posted By: HerrStig
Originally Posted By: John_K
Fits the "double it and add 30" adage I grew up with. And yes, 0 to 100 makes a heck of a lot more sense than 32 to 212.

John
except that the scale has fewer divisions.


With digital thermometers that display decimals I don't think that's an issue. In case of a conventional analog thermometer, would a scale that resolves 1/10°C exceed the resolution of a standard Fahrenheit thermometer? Below, my mercury thermometer showing 27.1 °C.

hotwheels

 

[HTSS_TR]

Originally Posted By: 757guy
I convert C to F all the time from hourly aviation reports.

C temp X 2 - 10% + Add 32 = F temp

Example:

19C X 2 = 38 - 10% (3.8) = 34.2 + 32 = 66.2F

I do the same estimate in my mind.

Converting F to C is just the opposite:
((F - 32) / 2) + 10% = C
Ex: 80F-32 = 48; 48/2 = 24 + 2 = 26.5C