Halīmah the daughter of Abū Dhu-aib as-Sa‘diyyah was one of the wet-nurses of the Prophet (ṣallá Allāhu ʿalayhi wa-sallam), she had kept the Prophet (ṣallá Allāhu ʿalayhi wa-sallam) and breastfed him, and when he was 2 years old she came back with him to Makkah to his mother, Āminah to return him... but in reality, she didn't want to return him!
She had been very pleased with him and had seen the amazing barakah (blessing) and goodness from his presence with her, something she had not experienced from other babies she had wet-nursed, so when she came to return him she actually intended to convince Āminah to let her keep him longer! So she mentioned the pleasant weather she had in her area as opposed to Makkah, and that she feared diseases upon him in Makkah (as opposed to the rural setting she had free of illnesses), and so she convinced Āminah and ended up keeping him longer and taking him back!
[Sharh al-Urjūzah al-Mī'iyyah (p 23), En. by Ustd. Abū Muadh (Twitter: AbuMuadhTaqweem) https://twitter.com/AbuMuadhTaqweem/status/1237667077546270720]