Sayyiduna Abdur-Rahman bin Abd al-Qari (may Allah have mercy on him) said that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said: Whoever misses his portion (of recitation) of the night, let him recite it from when the sun passes its zenith until Zuhr; then it is as though that portion was never missed, or as though he recited it on time.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4565