What time is "Jawf al-Lail" (midnight) approximately?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

According to Ibn al-Athir in his book "Ghareeb al-Hadith" and Ibn Mazoor 's book "Lisan al-'Arab", we state the issue as follows:
1) We divide the night into six parts.
2) So the Jawf al-Lail, "Midnight" starts from the beginning of the fifth part.
3) We count the hours of night from al-Maghrib to al-Fajr, and then, we divide them into six parts. So, the Jawf al-Lail begins from the start of fifth part till the end of night. But, this differs according to seasons and different countries where the length of night differs.
Allah knows best.