If it is 0 degrees today, the weather forecast says it will be twice as cold as today. What will it be tomorrow? (Please attach reasons)

This question is very interesting. I don't know if it really exists or is made up.

For the change of temperature (that is, how many times it is cold or how many times it is warm), it is necessary to compare two quantities, or both quantities are absolute, otherwise one is absolute and the other is variable, and it is impossible to compare.

So it is incomplete to say that tomorrow will be twice as cold as today, and it is impossible to know how cold it will be tomorrow.

There are two correct expressions:

1) Today is 8 degrees colder than yesterday, and tomorrow's cooling rate will be twice that of today. Ask about the temperature tomorrow.

2) Today the temperature is 0 degrees, and tomorrow it will be 2 degrees colder than today. Ask about the temperature tomorrow.