Is it recommended to stand out to receive rainwater at the beginning of rainfall?
Chapter on the Prayer for Rain (Istisqa)
Al-Mughni
Book of the Eclipse Prayers (Solar and Lunar)
Primary text
It is recommended to stand at the beginning of the rain and bring out one's rug or garment so that the rain may touch it. This is evidenced by the narration from Anas that the Prophet, peace be upon him, did not descend from his pulpit until the rain was seen streaming from his beard, as narrated by Al-Bukhari. Furthermore, Ibn Abbas, upon seeing the sky raining, would instruct his servant to bring out his rug and bedding for the rain to pour upon it.