-> BS> So 72F is about 21C?
->  
-> BS> I never got any use of the F unit, so never got a clue on how to
-> BS> calculate between celcius and fahrenheit.
->  
-> To determine the F reading, take the C, divide by 5, multiply by 9 and
add 32. 
-> For a faster, but less accurate way, you could simply multiply by 2.
->  



And Add 30.

((21C * 9) / 5) + 32 = 69.8f
(21c * 2) + 30       = 72F    (Not accurate but approximate)

---
.... Noise from Nik's Noo