A candle flame consists of three different zones. Each zone has different temperatures.
The first zone is the outer zone: Due to complete combustion, the outer zone is blue. This zone is the hottest when compared to the other zones. This blue coloured zone is the non-luminous part of the flame.
The second zone is the middle zone: The yellow coloured region which is the bright part of the flame is the middle zone. It is moderately hot and partial combustion of fuel takes place.
The third zone is inner zone: The inner zone is dark and mostly consists of unburnt wax vapours.