Is Duha Prayer to be recited aloud?

Recitation in Duha prayer is to be inaudible, like other daytime supererogatory prayers. The rule is that recitation in nighttime supererogatory prayers should be audible, and in daytime supererogatory prayers inaudible, except for what has been exempted, such as the two 'Eids and the prayer for rain (Istisqa'). It is recommended to recite audibly in nighttime supererogatory prayers and inaudibly in daytime supererogatory prayers. However, if a worshiper recites audibly in a daytime supererogatory prayer, that is permissible.