Covering the head    during prayer
Question

Is it a sunnah to wear a cap (or turban) especially during salat? I see many 'learned' brothers simply say that this is not sunnah and therefore pray without covering the head. Does Rasulullah Sallalahu Alaihi wassalam wear a turban or cap all the time even outside salat? Is this an Arab tradition or something that Allah recommended Rasul to do as an example to his ummah?
Praise be to Allah.Allah says (interpretation of the meaning):
O Children of Adam! Take your adornment (by wearing your clean clothes) while praying [Al-Araaf 7:31]
If covering the head is customarily regarded as a part of adornment in a particular country, then the head should be covered, otherwise it does not have to be covered.
And Allah knows best.