Short answer: because everything is stored in an integer (hardware limitations which cannot be changed), and there isn't a 1-to-1 correspondence between degrees in Celcius and degrees in Fahrenheit.
The long answer involves the temperature values being handed back and forth through several different objects, each with their own set of validation rules which change based on the temperature scale, and can be thrown out-of-range by the rounding errors.
From http://www.straightdope.com/mailbag/mtempscales.html
"Later, Fahrenheit, declaring a dislike of ""inconvenient and awkward fractions," decided to subdivide Rømer's degrees to allow for the measurement of finer temperature intervals, and so he divided each degree Rømer into 4 degrees Fahrenheit. He then tweaked the numbers so that the melting point of snow was 32 degrees and the temperature "in the mouth or under the armpit of a living man in good health" represented the 96th degree on his scale.
Fahrenheit added a further fixed reference point: the temperature of an equilibrium mixture of ice and salt-saturated water, which he defined as the zero point of his scale. Unfortunately, the use of three reference points added ambiguity rather than precision--the value of a degree varies by over 8% depending on which two of his reference points you choose. "
Uh yeah, why would anyone use Celcius?
XD
Read the original site for more horrid choices.
The best measure for scientific purpose is Kelvin, an absolute version of celsius where 0 is "no heat at all" (obviously not found in nature) and for everyday Celcius because freezing water is 0 and boiling water is 100 (at 1atm pressure). And human life is all about water and 1atm ^^
spot on bergamot
i always have to mentally rejig things back into inches, yards, miles, gallons, pints, and temp measures too.
I never voted (nor did anyone else) for the change to metric measures..nor did i vote to lose my country to the european superstate. And the majority of us didn't vote for Bliar's junta, nor this evil big brother state we now have.
/rant over
Please, blame the integer storage, the hardware limitations, the use of several different objects, the set of validation rules and the rounding errors (due to the use of integers too) but NOT the french decimal system now international system (the I in SI) ... ;-)
Standardisation saves lives when in critical apps everybody speak the same language (except when you change long habits without proper formation like if somebody decided to change feet to metres in aviation).
Me and a friend at school invented a metric time system (we're both huge simpsons fans). It doesnt help much. You have to remember time is based on planetary activity which makes it more difficult to bring into a nice round base 10 system. It is possible though... I even have a metric clock...somewhere.
Comments
I will probably spend tomorrow on it too.
The long answer involves the temperature values being handed back and forth through several different objects, each with their own set of validation rules which change based on the temperature scale, and can be thrown out-of-range by the rounding errors.
You'll have to excuse my ignorance, the only thing I've ever really programmed for is my own computer.
EDIT: just seeing your long answer, the main problem,then, is the rounding?
Anyway, I just needed to vent.
That's why we have 10 fingers and 10 toes, not 8, 12, 16 or 32! :-)
EDIT: I didn't read your question properly. If you are in the US, you are probably using Imperial.
That being said, I wonder why we don't have a metric version of time...