I don't use digital so I wanted to consider the boiling point also. I boiled water and moved the thermometer from ice bath to boiling to get an idea of not only how fast the thermometer approaches the final temp but how far off the readings were. Good data to have considering all of my thermometers reach a temp then slowly approach the actual temp.
One thermometer read 30F in the ice bath and 214 at boiling. I used interpolation to extract actual temps.
(Actual Temp - 32)/(212-32) = (Temp Read - 30)/(214-30)
or Actual Temp = ((212-32)*(Temp Read - 30)/(214-30))+32
Sometimes I wonder if its worth worrying over considering how hard it is for me to hit and maintain temps anyway.