Fog. New heartache coming from seasonal variation (6,2,7)

I believe the answer is:

change of weather

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'seasonal variation' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'fog new heartache coming from' is the wordplay.
'coming from' indicates an anagram.
'fog'+'new'+'heartache'='fognewheartache'
'fognewheartache' is an anagram of 'CHANGE OF WEATHER'.

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I've seen this clue in the Sydney Morning Herald.

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