Ibn Mandhour said: “Shawwaal is one of the well known names of months, the name of the month which follows Ramadaan and is the first of the months of Hajj.” 

It was said that it was called after the drying up of the camels’ milk (tashweel), 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 (shaalat) her tail. The Prophet (peace and blessings of Allaah be upon him) declared their superstition to be false. ‘Aa’ishah (may Allaah be pleased with her) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) married me in Shawwaal and consummated the marriage with me in Shawwaal, 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 in his Saheeh, 2/1039, Kitaab al-Nikaah, hadeeth no. 1423. Also narrated al-Tirmidhi in his Sunan, 2/277, Abwaab al-Nikaah, hadeeth no. 1099; he said it is a saheeh hasan hadeeth. Also narrated by al-Nasaa’i in his Sunan, 6/70, Kitaab al-Nikaah, Baab al-Tazweej fi Shawwaal. Also narrated by Ibn Maajah in his Sunan, 1/641, Kitaab al-Nikaah, hadeeth no. 1990. (Lisaan al-‘Arab, 11/277, heading Shawwaal). 

The reason why the Arabs of the Jaahiliyyah were so superstitious about marrying during Shawwaal 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 Katheer (may Allaah have mercy on him) said: “The fact that the Prophet (peace and blessings of Allaah be upon him) consummated his marriage with ‘Aa’ishah (may Allaah be pleased with her) during Shawwaal 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-Bidaayah wa’l-Nihaayah, 3/253) 

Being superstitious about getting married in Shawwaal is the matter of falsehood, because superstition in general is part of the “evil omen” (tiyarah) that the Prophet (peace and blessings of Allaah be upon him) forbade when he said, “There is no contagion and no evil omen.” (Sharh Saheeh Muslim li’l-Nawawi, 14/219, 218). And he (peace and blessings of Allaah be upon him)

Said, “Tiyarah (believing in evil omens) is shirk.”

(Narrated by Imaam Ahmad in his Musnad, 1/440. Also narrated by Abu Dawood in his Sunan, 4/230, Kitaab al-Tibb, hadeeth no. 3910). Also narrated by al-Tirmidhi in his Sunan, 3/84, 85, Abwaab al-Siyar, hadeeth no. 1663; he said, it is a saheeh hasan hadeeth. Also narrated by Ibn Maajah in his Sunan, 2/1170, Kitaab al-Tibb, hadeeth no. 3538. Also narrated by al-Haakim in al-Mustadrak, 1/17, 18, Kitaab al-Eemaan; he said it is a hadeeth whose isnaad is saheeh and its narrators are thiqah, although they al-Bukhaari and Muslim did not narrate it; al-Dhahabi agreed with him in his Talkhees). 

Al-Nawawi (may Allaah have mercy on him) said in his commentary on the hadeeth of ‘Aa’ishah (may Allaah be pleased with her): “This indicates that it is mustahabb to get married and to consummate the marriage in Shawwaal. Our companions fellow-scholars have stated that this is mustahabb, quoting this hadeeth as evidence for that.” 

By saying this, ‘Aa’ishah was aiming to refute the ignorant belief of the Jaahiliyyah, and what some of the common folk still believe today, that it is makrooh to get married or to consummate the marriage in Shawwaal. This is false and there is no basis for this belief. It is one of the leftovers of the Jaahiliyyah, when they used to be superstitious about that because of the connations of the name of Shawwaal which related to the drying up of the camel’s milk and the lifting of its tail…”

(Sharh Saheeh Muslim li’l-Nawawi, 9/209) 

al-Bida’ al-Hawliyyah by Shaykh ‘Abd-Allaah ibn ‘Abd al-‘Azeez ibn Ahmad al-Tuwayjri, p. 348-349