Musnad Ahmad 30:2004

Yunus narrated to us, he said: Aban—meaning al-Attar—narrated to us, from Yahya ibn Abi Kathir, from Muhammad ibn Abd al-Rahman ibn Thawban, from Abu Hurayrah: "That Hellfire asked permission from its Lord, so He allowed it to exhale twice every year; so the intensity of the heat is from the heat of Hellfire, and the intensity of the cold is from its freezing cold (zamharir)." And Abu Hurayrah said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the heat intensifies, then delay the prayer until it cools down, for the intensity of the heat is from the scorching breath (fayh) of Hellfire."