ANSWER:

This is not true. You can make wudu over your limbs irrespective of whether it is wet or dry.

QUESTION: They have said that our hair must not be wet before we wipe our hands over our head in wudhu, is this true? They also said our feet must be dry before we wash them in wudhu, is this true? What if water goes on our feet and hair must we dry it then continue wudhu? Or does it not matter whether our body, hair or feet are wet and we can just continue and make our wudhu?