It is part of sunnah to supplicate with qunut in the witr prayer during the entire year. Ahmad, at-Tirmizhi, an-Nasa’i, Abu Dawud, Ibn Majah, and others record that al-Hassan ibn ‘Ali said: “The Messenger of Allah taught me the [following] words to say in the witr prayer: ‘O Allah, guide me among those whom You have guided. Grant me safety among those whom You have granted safety. Take me into Your charge among those whom You have taken into Your charge. Bless me in what You have given me. Protect me from the evil that You have decreed, for You decree and nothing is decreed for You. And there is no humiliation for whom You take as a ward. Blessed and Exalted are You, our Lord.'”
At-Tirmizhi grades this hadith as hasan, and says: “… nothing is known from the Prophet concerning qunut more authentic than that.” Commenting on its status, an-Nawawi says that its chain is sahih. Ibn Hazm has some reservations about its soundness, but says: “This hadith, although it is not one that can be used as a proof, is all that we have from the Prophet, and a weak hadith is dearer to me than mere opinion.” Ahmad says this is also the view of Abu Musa, Ibn Mas’ud, Ibn ‘Abbas, al-Bara’, Anas, al-Hassan al-Basri, ‘Umar ibn ‘Abdul’aziz, al-Thauri, Ibn al-Mubarak, and the Hanafi school. This, an-Nawawi says, gives credibility to the report.
Ash-Shaf’i and others are of the opinion that the qunut in the witr prayer should be made during the latter half of the month of Ramadan. This is based on what Abu Dawud records that, ‘Umar ibn al-Khattab convoked the people in prayer, under the leadership of Ubayy ibn Ka’b, and they prayed together for twenty nights, and he did not make the qunut except for during the latter half of the month of Ramadan. It is moreover related that Muhammad ibn Nasr asked Sa’id ibn Jubair about the qunut in the witr prayer. Sa’id answered: “‘Umar sent an army that suffered serious setback, which caused ‘Umar to be alarmed, so, when it was the latter half of Ramadan, he made the qunut to supplicate for them.”