Urwah bin al-Zubayr (may Allah have mercy on him) narrates that he (peace and blessings be upon him) said: "When one of you sees rain or lightning, let him not point at it, but rather let him describe and praise it."
Sulayman bin Abdullah bin Uwaymir narrates it from Urwah, in the lengthy (book) which we heard from Abu Sa'id (may Allah have mercy on him).
Abdullah bin Uwaymir narrates: I was with Urwah bin al-Zubayr (may Allah have mercy on him), and I pointed at the clouds with my hand. He said: Do not do that, for the Messenger (peace and blessings be upon him) "forbade that it be pointed at." Ibn Abi Husayn (may Allah have mercy on him) narrates that the Prophet (peace and blessings be upon him) "forbade pointing at the rain." This narration is mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6473
It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) forbade pointing at the rain.
It has also been narrated through another, weak chain.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6474