Sayyiduna Anas (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) performed four Umrahs, all of them in Dhul-Qa'dah, except the one he performed along with his Hajj: one, the Umrah of al-Hudaybiyah, in Dhul-Qa'dah; an Umrah the following year in Dhul-Qa'dah; an Umrah from al-Ji'ranah, when he distributed the spoils of Hunayn, also in Dhul-Qa'dah; and one Umrah along with his Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8792