What is the average temperature of the flame of the candle?

Depending on the wax, and the concentrations of water of oxygen in the air, somewhere between 1,200 degrees and 1,700 degrees Celsius.

The heat capacity and conductivity of air and the exhaust products of combustion, however, are both very low. In practice, candle flames do not seem very hot (much like metal feels colder than wood at room temperature, though they are the same temperature).

The outer core of the candle flame is light blue -- 1670 K (1400 °C). That is the hottest part of the flame. The color inside the flame becomes yellow, orange and finally red. The further you reach to the center of the flame, the lower the temperature will be. The red portion is around 1070 K (800 °C). The reason there is this variation in a candle's flame color is because air convection pulls the warmer gasses upwards.