The “last third of the night” is the final one‑third of the time between Maghrib (sunset) and Fajr (true dawn).

Basic idea in one line

Night in this context starts at Maghrib and ends at Fajr; you divide that span into three equal parts, and the final part is the last third of the night.

How to calculate it (step‑by‑step)

  1. Note the time of Maghrib for today.
  1. Note the time of Fajr for tomorrow.
  1. Calculate how many hours and minutes there are between Maghrib and Fajr.
  1. Divide that duration by three; that gives you the length of one third of the night.
  1. Subtract one third from Fajr time: the result is when the last third begins; it lasts until Fajr.

Example

  • Maghrib: 6:00 pm
  • Fajr: 5:00 am
  • Total night: 11 hours.
  • One third: about 3 hours 40 minutes.
  • Last third begins: 5:00 am − 3 h 40 min ≈ 1:20 am, and continues until Fajr at 5:00 am.

Why this time is emphasized (Islamic perspective)

In many Islamic teachings, this last third is described as a special time when Allah turns to the lowest heaven and calls His servants to supplicate, seek forgiveness, and ask for their needs. Because of this, it is widely recommended for Tahajjud and duʿa in that period.

A simple way people remember it: “Find Maghrib and Fajr, slice the night into three equal chunks; pray and make duʿa in the final chunk.”

Seasonal and location differences

  • The last third shifts through the year because nights are longer in winter and shorter in summer.
  • Different locations have different Maghrib and Fajr times, so the exact clock time of the last third is always local and date‑specific.

Many people now use “last third of the night” calculators where you enter your city and date, and it automatically computes the interval for you.

Quick takeaway (TL;DR)

“Last third of the night” = from “two‑thirds of the night have passed” up to Fajr, where “night” runs from Maghrib to Fajr, and you find it by dividing that whole stretch into three equal parts.

Information gathered from public forums or data available on the internet and portrayed here.