Due to a lot of reason, the names of months in Arabic calendar varies from region to region in the Arab World. Although, the Gregorian calendar is the one which is globally accepted for daily use, your location decides which calendar is being used in a particular region. For example, you may find Aramaic and Babylonian Calendar months being used extensively in some area. The best thing is that the current date does not change in these calendars except for Saudi Arabia which uses a different rule. So, this means the dates will not change anywhere in the Arab world. However, names of the months are used differently in the Arab world. The reason is many countries have renamed the Gregorian calendar, for example, Syria renamed the Gregorian calendar after the Aramaic counterparts, which are typically based on the Babylonian calendar.
Let’s take an example, in the Levant (Lebanon, Palestine, Jordan, and Syria), the month of May is referred to as أيار. Now أيار (‘Ayyār) is the Aramaic name for May. If you go further south to Egypt and Sudan, you will find out that May is مايو (māyū), as these countries use the Gregorian calendar. Now if you go much further to Algeria and Morocco, there is only a slight variation and the results are kind of similar. Here مايو (māyū) becomes ماي (Mai), which is actually based on the French names of Gregorian months.
Again, there are special cases that differ from the above-shown patterns: Libya’s calendar months are procured from multiple sources, then chosen and assembled by its leader Mu’amar al-Ghaddafi. May in Libya is الماء (alma’), which means “water”. The other exception which I mentioned earlier is Saudi Arabia where Islamic calendar months are the only norm and are used concurrently with Gregorian ones. May in Saudi Arabia is either جمادى الأول or جمادى الثاني . The two names depending on what part of May you find yourself in or talking about. All of this is due to the fact that the Islamic calendar dates lack Gregorian calendar equivalents. So, according to the Islamic calendar, today’s date is “al-‘ithnayn: 23. Radjab 1439” (9th April 2018 in Gregorian). The Islamic calendar first year is based on the year in which the Prophet Muhammad left the city of Mecca and headed to Medina, 622 CE.