[550] Sāvatthī. Sitting to one side, that bhikkhu said this to the Blessed One: "Venerable sir, what is the cause, what is the condition, whereby at times it is hot?"
"Bhikkhu, there are devas called warm-cloud devas (uṇhavalāhakā devā). When it occurs to them thus: 'What if we were to delight in our own delight?' then, in accordance with that mental resolve (cetopaṇidhi) of theirs, it becomes hot. This, bhikkhu, is the cause, this is the condition, whereby at times it is hot."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.