Why is it bad to use myFile.print()? Printing the sensor values directly to the sd card keeps them the same number of characters each entry, so I am confused why I should not do it this way.
Stick that probe in a pot of boiling water. What happens when it goes over 99.999 degrees?
Stick it outside in Alaska in the middle of winter. Say, around June. What happens when the temperature goes below 0?