Hotel north of the border (not self-catering) is a bit warm (7)

'warm' is the definition.
Both the answer and definition are adjectives.
Maybe you can see an association between them that I don't see?

'hotel north of the border not self-catering is a bit' is the wordplay.
I cannot really understand how this works, but
'hotel' could be 'h' (phonetic alphabet) and 'h' is found within the answer.
'of' could be 'o' and 'o' is located in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
'is' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?