Glove in cold season without top temperature is on and off (12)
I believe the answer is:
intermittent
'is on and off' is the definition.
(I've seen this before)
'glove in cold season without top temperature' is the wordplay.
'glove' becomes 'mitten' (mitten is a kind of glove).
'in' indicates putting letters inside.
'cold season' becomes 'winter' (coldest time of year).
'without top' means to remove the first letter.
'temperature' becomes 't' (abbreviation).
'winter' with its first letter taken off is 'inter'.
'inter'+'t'='intert'
'mitten' put into 'intert' is 'INTERMITTENT'.
(Other definitions for intermittent that I've seen before include "Occasional" , "Occurring at intervals" , "Irregular" , "Not continuous or steady" , "On-and-off" .)