Temperature to the north rising, say (3)
I believe the answer is:
put
'say' is the definition.
(thesaurus)
'temperature to the north rising' is the wordplay.
'temperature' becomes 't' (abbreviation).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'the north' shows that the letters should be reversed in order (in a down clue, letters go up or 'north').
'rising' becomes 'up' (similar in meaning).
'up' backwards is 'pu'.
't' after 'pu' is 'PUT'.
(Other definitions for put that I've seen before include "Set (in place)" , "Place in a location" , "Place; placed" , "Place in a position" , "Place, lay" .)