In English, shouldn't it be it 'the coldest' than 'coldest'?
I've heard it said as just "Coldest" when people are describing the weather.
When would 'kallast' be 'kallaste'? What would mean that you would add an 'e' to the end of a superlative?
Is there a particular difference between "kall," and "köld"? If not, is there a word better suited to "cool" as a temperature? Tack mycket.
kall is an adjective but köld is a noun.
cool as an adjective is kylig or sval (sval often has a nuance of 'refreshingly cool' to it).