This is the blessed mosque where the Prophet (peace and blessings of Allaah be upon him) once went out in the scorching sun when Madinah was in the form of famine and even animals and trees, including humans, dried up.
He prayed for rain in the presence of Allah (swt). During the du'a, a piece of cloud fell on the blessed head of the Prophet (sws) and immediately it started raining in Madinah and the whole Madinah became green.
The mosque built on this occasion was named "Masjid Ghamama" because in Arabic Ghamama is called "cloud".
In addition, the Prophet (peace and blessings of Allaah be upon him) offered Eid prayers at this place and also sacrificed camels and sheep.
On the site of the Ghamama Mosque, the Prophet (peace be upon him) announced the death of the king of Abyssinia, Najashi, who loved the Prophet (peace be upon him) very much and had entered the realm of Islam. The day he died even though there was no means of communication at that time - and the Prophet (peace and blessings of Allaah be upon him) offered the funeral prayer in absentia at the same place.