I heard recently that the temperatures in parts of Canada were 20 degree Celsius below normal. When I converted that to the Fahrenheit scale using my calculator, I got temperatures that were 68 degrees below normal. This does not sound right. This is a very common mistake.
Most calculators only calculate the first conversion.
Fahrenheit are what you read on a thermometer scale. Celsius degrees or Fahrenheit degrees are the intervals between the gradations on that thermometer scale. When we talk about temperature readings, we are actually referring to degrees Celsius or degrees Fahrenheit. But when we talk about differences between two temperatures, we should use Celsius degrees or Fahrenheit degrees. The degree in the Celsius scale is larger than the Fahrenheit equivalent.