Is Marriage in Shawwal Disliked?
Question

Is what people say about avoiding getting married in Shawwal correct?
Praise be to Allah.Ibn Mandhur (may Allah have mercy on him) said: “Shawwal is one of the well-known names of months, the name of the month which follows Ramadan and is the first of the months of Hajj.” 
It was said that it was called after the drying up of the camels’ milk (Tashwil), when it becomes scanty. This is what happens to the camels when the heat becomes intense and there are no longer any dates on the palm trees… 
The Arabs were superstitious about getting married at that time, and they would say that the bride would keep away from her groom like the female camel when she has been impregnated and lifted (Shalat) her tail. 
The Prophet (peace and blessings of Allah be upon him) declared their superstition to be false. `Aishah (may Allah be pleased with her) said: “The Messenger of Allah (peace and blessings of Allah be upon him) married me in Shawwal and consummated the marriage with me in Shawwal, and which of his wives was more favoured by him than me?” (Narrated by Ahmad in Al-Musnad, 6/54; this version narrated by him. Also narrated by Muslim, 2/1039, Kitab An-Nikah, 1423. Also narrated At-Tirmidhi in his Sunan, 2/277, Abwab An-Nikah, 1099; he said it is an authentic Hadith. Also narrated by An-Nasa’i in his Sunan, 6/70, Kitab An-Nikah, Bab At-Tazwij fi Shawwal. Also narrated by Ibn Majah in his Sunan, 1/641, Kitab An-Nikah, 1990. Lisan Al-`Arab, 11/277, heading Shawwal)
The reason why the Arabs of the Jahiliyyah were so superstitious about marrying during Shawwal was that they believed that a woman would keep away from her husband like the she-camel that has lifted (Shawwalat) its tail after being impregnated keeps away from the he-camel. 
Ibn Kathir (may Allah have mercy on him) said: 
“The fact that the Prophet (peace and blessings of Allah be upon him) consummated his marriage with `Aishah (may Allah be pleased with her) during Shawwal was a refutation of the notions that some people held, that it was disliked to consummate a marriage between the two `Eids, lest that lead to separation of the spouses. But that was a false notion.” (Al-Bidayah wan Nihayah, 3/253) 
Being superstitious about getting married in Shawwal is the matter of falsehood, because superstition in general is part of the “evil omen” (Tiyarah) that the Prophet (peace and blessings of Allah be upon him) forbade when he said, “There is no contagion and no evil omen.” (Sharh Sahih Muslim, 14/219, 218). And he (peace and blessings of Allah be upon him) said, “Tiyarah (believing in evil omens) is Shirk.” (Narrated by Imam Ahmad in his Musnad, 1/440. Also narrated by Abu Dawud in his Sunan, 4/230, Kitab At-Tibb, 3910. Also narrated by At-Tirmidhi in his Sunan, 3/84, 85, Abwab As-Siyar, 1663; he said, it is an authentic Hadith. Also narrated by Ibn Majah in his Sunan, 2/1170, Kitab At-Tibb, 3538. Also narrated by Al-Hakim in Al-Mustadrak, 1/17, 18, Kitab Al-Iman; he said it is a Hadith whose Isnad (chain of narration) is authentic and its narrators are trustworthy, although they [Al-Bukhari and Muslim] did not narrate it; Adh-Dhahabi agreed with [the ruling of] Al-Hakim in At-Talkhis). 
An-Nawawi (may Allah have mercy on him) said in his commentary on the Hadith of `Aishah (may Allah be pleased with her): “This indicates that it is recommended to get married and to consummate the marriage in Shawwal. Our companions [fellow-scholars] have stated that this is recommended, quoting this Hadith as evidence for that.” 
By saying this, `Aishah (may Allah be pleased with her) was aiming to refute the ignorant belief of the Jahiliyyah, and what some of the common folk still believe today, that it is disliked to get married or to consummate the marriage in Shawwal. This is false and there is no basis for this belief. It is one of the leftovers of the Jahiliyyah, when they used to be superstitious about that because of the connotations of the name of Shawwal which related to the drying up of the camel’s milk and the lifting of its tail…” (Sharh Sahih Muslim, 9/209) 
For more details about the month of Shawwal, please see the following answers: 7860 , 7858 , 40389 , and 106468 . 
And Allah knows best.