Is the Duha prayer to be performed on a cloudy and rainy day according to its time recorded in the official calendar, even if the sun does not appear throughout the day?

The Duha prayer is legislated when the sun has risen about a spear-length after sunrise. The time of prohibition (for prayer) after sunrise is estimated to be about fifteen minutes. The crucial factor is the entry of the time, not the visible sighting of the sun. A calendar can be used to determine the time of sunrise.