If a person missed a Fardh or Witr Salaat, he has committed a major sin. He has to make Qadhaa (make up) for the missed Salaats as well as make sincere Tawbah to Allah Ta’ala.
One should fulfil his/her Qadhaa Salats as soon as possible. Death is imminent and one should always be conscious of that. Qadhaa Salaat may be performed any time during the day or night, besides the following times; a) At sunrise, b) Midday, c) Sunset and d) After Asr Salaat, after the sun loses its brightness and glow.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai