Converting Temperature Scales

Having just returned from Columbia, South America, I realized the usefulness of a quick conversion method from Celsius to Fahrenheit that I learned quite some time ago. For us Americans who only think in terms of our temperature scale, this method gives a quick conversion without any mental gyrations. I found it very handy while I was out of the country and I am sure you will find it useful as well.

The equation relating Fahrenheit to Celsius is as follows: F = 9/5C + 32, where obviously F stands for temperature Fahrenheit and C for Celsius. At first glance it would seem that a simple way of converting between the two temperature scales based on this formula is not available. Yet the following method is exact and works very nicely. Given a temperature in Celsius, simply multiply it by 2; then subtract 10%, which is nothing more than a decimal shift on the number, a decimal shift to the left that is, and then add 32. That is all there is to it. The resulting temperature will be the exact Fahrenheit conversion.

The reason why this works can be seen if you look at the equation above relating both Fahrenheit and Celsius; 9/5 is the same as 1.8, and this is 0.2 less than 2. Thus when you double and then take away 10%, you are actually multiplying the Celsius temperature by 1.8 or 9/5. You then simply add 32 to arrive at the correct Fahrenheit temperature.

Let’s see how nice and quickly this method works with some temperatures in Celsius. Take a nice hot sunny day in Columbia with a temperature of 30C. The Fahrenheit temperature is derived by doubling to get 60, subtracting 10% or 6 (a one decimal shift to the left from 60), and then adding 32 to get 60 – 6 + 32 or 86F. Or take a blisteringly hot day of 35C. Double to get 70, subtract 10% of this or 7 to get 63, and add 32 to get 95.

That is all there is to converting from Celsius to Fahrenheit. So on your next trip abroad, don’t get flustered by the temperatures given in Celsius. Just use our handy method to arrive at the temperature in Fahrenheit. And, oh, don’t forget to enjoy the climate.