The reference point for the Islamic day/date almost everywhere is the time of sunset. In this way 24 hours will have elapsed on the following day at sunset. There are two days (day of Arafat & day of Qurbaani) which are an exception and even these are only for the Pilgrim in Makkah. The 9th of Dhul Hijjah (Arafat day) commences at SUBH-E-SAADIQ and ends at SUBHE-E-SAADIQ of the 10th Dhul Hijjah. Similarly, the day of Qurbaani (10th of Dhul Hijjah) commences from daybreak.


In contrast to the lunar day, the conventional solar day begins at 12 o'clock midnight and continues until 12 o'clock on the subsequent night. This conventional day has been divided into 24 time zones. All places in one zone will have a common time (eg 12 o'clock) while a place which is only a few meters away in the west will be an hour behind (11 o'clock) and a place on the east will be an hour ahead (1 o'clock).

Fig3 WorldTimeZones
Figure 3. World Time-Zones

The difference between lunar and conventional solar day/date/s may be summarised as follows:

LUNAR DAY/DATE: From SUNSET TO SUNSET=one day (sunset-night­ sunrise-day-sunset).

CONVENTIONAL DAY/DATE: From MIDNIGHT TO MIDNIGHT=one day (midnight-sunrise-day-sunset-midnight).

This means that the lunar day (Islamic day) always cycle between two solar dates.


There was no standard calendar in the Arabian Peninsula before Islam. Every Tribe and Area had its own method. Among these, a version of the "Nasa'ee" calendar was also in use. When the Holy Prophet (ﷺ) arrived in Medina and met the Jewish clans, he found them using the Hebrew solar/lunar calendar which differed in some ways to the Arab calendars. In the 4th Century (C.E.), Hillel, a Jewish leader took into account the past 1000 years and formulated a calendar which he recommended to the Jews the world over. This calendar is still in use to date by the Jews.

The Jewish calendar is a lunar/solar calendar similar to the "Nasa'ee". Every third year an extra month is added to bring the year in accord with the solar year and with the season. In this calendar, the new month is commenced with the Astronomical New Moon (unobservable by the naked eye). This is the reason why there used to be a difference of usually one and sometimes 2 days between their months and the months of the Muslim (Arab) calendar.