Urban Heat is a female-founded neighbourhood sauna and cold plunge under railway arch 347 on Camberwell Station Road in south London. It combines a spacious 15-seater Finnish-style sauna kept at 90 to 95 °C with three outdoor ice baths at 5 and 10 °C and a lounge, and runs communal, quiet, same-gender, parent-and-baby and 90-minute guided sessions with breathwork and aromatics. Private hire is available; memberships start at £23 a month and a five-session Heat Pass is £75.