Time of Marriage Ceremony Nikaah in Islam

Though basically marriage is allowed at all times, there are some days on which marriage is not recommended; some of these are based on ahadith and some on cultural, historical reasons.
Generally, we can categorize these days into three:

(a) There are some ahadith which say that it is makruh (not recommended) to have a marriage ceremony on the days when the moon is in the constellation of Scorpio (this is known as al-qamar fil aqrab or qamar dar aqrab), during the last two or three days of the lunar months, and on Wednesdays.

(b) There are certain days of the Islamic calendar which have become associated with the early events of the Islamic history; for example, the 10th of Muharram is the day of mourning for the massacre at Karbala or the day of the Prophet’s death in Safar, etc. Since such days are commemorated by the Muslims as days of mourning, it is socially and, to some extent, religiously not recommended to have a marriage ceremony on such days.
The Shia Ithna Ashari (Twelver Shias), especially in India and Pakistan, rarely perform marriage ceremony between the 1st of Muharram and the 8th of Rabi al-Awwal as this period includes the mourning days of Muharram culminating in the martyrdom of Imam Askari (a.s.). The 9th Rabi al-Awwal is celebrated as Eid-e-Zahra.
If there is a need, however, Nikah, can be performed at any time.