If it’s zero degrees today and twice as cold tomorrow, how many degrees will it be?

Answer

If you take “something” twice, you can only do that if that “something” itself is a number.

– If something is 3 meters long, twice as long is 6 meters.
– If something weighs 25 kilograms, then it weighs twice as much as 50 kilograms

To be able to speak of “twice as cold” you must first convert the term “cold” into a number, which you can then multiply by two.

How are you going to convert “cold” into a number? How are you going to do that? In degrees Celsius, in Kelvin, in degrees Fahrenheit ?
What is cold to one person may not be to another. Cold is not a number, cold is a feeling and it varies from person to person. So I don’t think you can just come up with a formula to calculate whether something is twice colder than something else.