Temperature from historic times had an effect (4)
I believe the answer is:
told
'had an effect' is the definition.
(I've seen this in another clue)
'temperature from historic' is the wordplay.
'temperature' becomes 't' (abbreviation).
'from' says to put letters next to each other.
'historic' becomes 'old' (historic can mean very old).
't'+'old'='TOLD'
'times' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for told that I've seen before include "Produced effect; related" , "Made an impact" , "Informed; narrated" , "Authorised - broadcast" , "Said" .)