Is a woman's prayer invalid unless it is under a roof or with a barrier between her and the sky?

It is incorrect that a woman is not allowed to pray except under a roof. The generality of the Prophet's saying, "The earth has been made for me a mosque and a means of purification, so any man from my Ummah who is overtaken by prayer should pray," indicates the validity of prayer in any place. For a woman's prayer to be valid, she must cover her entire body except for her face and hands, according to the Prophet's saying, "Allah does not accept the prayer of a menstruating woman except with a head covering," and Umm Salamah's statement, "Can a woman pray in a dir’ (chemise) and khimar (head covering) without an izar (lower garment)?" He replied, "If the dir’ is ample, covering the tops of her feet."