Question: what is the difference between primer annealing temperature and melting temperature?
Answer: "Primer Melting Temperature (Tm) by definition is the temperature at which one-half of the DNA duplex will dissociate to become single stranded and indicates the duplex stability. Primers with melting temperatures in the range of 52-58 oC generally produce the best results." ... Annealing temp should be 5C below Tm.