All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Ahmad, At-Tirmithi, Ad-Daarimi and Abu Ya’la, may, Allaah have mercy on them, reported that Abu Sa’eed Al-Khudri narrated that the Prophet said: "The dreams that are most likely to come true are those seen in the last part of the night.’’ The chain of narrators of this narration is weak, nonetheless, the scholars, may, Allaah have mercy on them, stated that its meaning is correct. For instance, Ibn Al-Qayyim said: "The dreams that are most likely to come true are those seen in the last part of the night, as this is the part of the night in which Allaah descends to the first heaven, and the time Allaah’s Mercy and Forgiveness are near, and it is the time the devils are quiet…"
Al-Munaawi said about the reason why the dreams in the last part of the night are most likely to come true:"That is because of the excellence of the time by the spread of mercy and the spread of peace of heart and body attained by sleeping and being in total rest."
Therefore, the dream that a person sees before Fajr might come true more than the dream that one sees after Fajr.
Allaah Knows best.