Holiday little bit warmer? (7)
I believe the answer is:
whitsun
'holiday' is the definition.
(I know that Whitsun is a type of religious festival)
'little bit warmer?' is the wordplay.
'little bit' becomes 'whit' (I've seen this in another clue).
'warmer?' becomes 'sun' (the sun warms things up).
'whit'+'sun'='WHITSUN'
(Other definitions for whitsun that I've seen before include "Holy Spirit festival" , "Wins hut on short Christian Sabbath" , "Feast" , "Pentecost season" , "Period seven weeks after Easter" .)