The sources I looked at (e.g. [0]) suggest a maximum temperature of 91 F with a humidity of maybe 72 %, equating to a wet bulb of 28.51 C [1].

Are you sure about those temperatures/humidities? 100 F with 99 % humidity equates to a wet bulb of 37.75 C [2], well above the commonly accepted theoretically survivable limit of 35 C.

[0] https://www.weatherwx.com/hazardoutlook/sc/fort+jackson.html

[1] https://www.omnicalculator.com/physics/wet-bulb?advanced=1&c...

[2] https://www.omnicalculator.com/physics/wet-bulb?advanced=1&c...