Time of year to secure time in office? Not quite (6)
I believe the answer is:
winter
'time of year' is the definition.
(winter is a kind of time of year)
'secure time in office? not quite' is the wordplay.
'secure' becomes 'win' (I've seen this in other clues).
'time in office?' becomes 'term' (eg a presidential term).
'not quite' means to remove the last letter.
'term' with its final letter removed is 'ter'.
'win'+'ter'='WINTER'
'to' is the link.
(Other definitions for winter that I've seen before include "Coldest season" , "Time for mittens and scarves?" , "period of freeze?" , "period of discontent?" , "'If . . . . . . comes, can spring be far behind?'" .)