The Peripatetic Historian explores the wonders of the Hagia Sophia, the Basilica Cistern, and tangles with the Whirling Dervishes — An August day in Istanbul is, in a single word, hot. If you required a second adjective, “humid” would do nicely. Or “sweaty.” My first morning in Istanbul is a perspiration provoker and the weather forecast signals no imminent relief. Supposed to be in the low 90s throughout my stay.