30 Months

"And We have enjoined on man doing of good to his parents; with trouble did his mother bear him and with trouble did she bring him forth; and the bearing of him and the weaning of him was thirty months; until when he attains his maturity and reaches forty years, he says: My Lord! grant me that I may give thanks for Thy favor which Thou hast bestowed on me and on my parents, and that I may do good which pleases Thee and do good to me in respect of my offspring; surely I turn to Thee, and surely I am of those who submit."

[Al-Quran 46:15]

30 months, pardon my ignorance about period of breastfeeding being 24 months. Al-Quran 2:233 states 24 months. 

Someone help me with tafseer, please?

In any case, happy nursing, fellow mamas out there!