Is it permissible for someone in the state of Ihraam to use an umbrella to protect his head from the heat of the sun?
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It is permissible for a person in the state of Ihraam (ritual consecration) to put something on his head to protect himself from the heat or rain (provided it does not touch his head). This ruling also applies to a person outside the state of Ihraam with greater reason. It is narrated on the authority of Umm Husayn, may Allah be pleased with her, that she said, "I performed Hajj with the Messenger of Allah (may Allah exalt his mention), in the Farewell Hajj. I saw Usaamah and Bilaal, or one of them, holding the noseband of the she-camel of the Prophet while the other was shading him with his garment to protect him from the heat until he threw the pebbles at Jamrat Al-‘Aqabah (the large pillar)." [Muslim]
Commenting on this Hadeeth, Ash-Shawkaani said in his book entitled Nayl Al-Awtaar, "The Hadeeth implies the permissibility of shading one's head with a garment or something he is carrying, and so on. This is the opinion adopted by the majority of the scholars”.
Allah Knows best.