Good point. I was thinking of a regular pool or natural body of water, which for the most part are usually cooler than a persons body temperature. I would definitely not recommend swimming in a hot tub during a heat event.

Yeah that’s exactly what happens. Where I live in Canada, in the summer there is the air temperature, and then there is the ‘humidex value’. So it can be 25 degrees Celsius but with the humidity it will “feel like” 30 degrees Celsius. It gets dangerous when the air temperature is already in the 30 degree range and the humidity makes it feel closer to 40 or higher. Then we get heat warnings for people to be careful because you can get heat stroke pretty easily.

It’s like being in a steam sauna but you’re outside and can’t escape it. High heat and humidity are brutal. Also see ‘wet bulb effect’. Sweating does absolutely nothing to cool you off. Swimming can help as long as the water is cooler than the air temperature.