Yeah, it is allowed. (temp-baseline)/baseline

Ana

Thank you Ana. I submitted my paper for publication the reviewers accepted the percentage change in temperature but the editor recommend the followings:

' it is very unusual to use percentage to describe temperature change (it is commonly used for precipitation change, however), so that my recommendation is to avoid this throughout the paper,'

Ana do you have any publication that presented temperature as percentage change in future climate projection?

Hi Philbert,

I  was asked this last year and found the quickest way to explain this is to use someone else's explanation!

Dear Tom,

I say that a temperature rise from 50(degrees) F. to 100(degrees) F. is a 100 percent increase, but a friend says that is wrong. What's your take?

Fred Marshall, Rockford, Ill.

Dear Fred,

Your arithmetic is correct but your result is arbitrary. When expressing a temperature change as a percentage, one must use a temperature scale whose zero point is the temperature of absolute zero, and then use that selected scale consistently. The Kelvin scale is such a temperature scale. All other temperature systems, like Fahrenheit and Celsius, have arbitrary "zero points," and calculations of percent temperature change using those scales will give arbitrary results.

In the example you provided, on the Fahrenheit scale the temperature rise is 100 percent (from 50(degrees) to 100(degrees) F.), but that same change on the Celsius scale is 280 percent (from 10 to 38 C.). Using the Kelvin scale, whose zero point is absolute zero (-460(degrees) F., -273(degrees) C.), the rise is actually 10 percent, from 283(degrees) to 311(degrees) K.

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Tom Skilling is chief meteorologist at WGN-TV.

Dear Peter thank you very much for clarification.

I agree with the response above about the dependence of the percent change on the units chosen.  One thing you might consider, especially if you are studying the tropics, is evaluating how hot a "normal" day in the future compared to a "hot" day in the present. In other words, where would an average temperature in 2070-2099 fall on a histogram of the 1971-2000 temperatures.