Wet bulb pertains to the low temperature being too high, not the highs. It is getting cool enough at night in Britain that it’s nowhere close to wet bulb
Humidity is a factor too, but it’s less about acute heat strokes from extreme highs and more about extended periods of time with no cooloff periods during the night so ambient body temperature is never able to stabilize. It also only pertains to places with no place where the public can easily go to cool off every once and a while, such as air conditioned malls or museums or the like.
Yeah, my family is from the Hudson Bay area and i'm not the worst in heat, but i'm not a fan of humidity. Would rather work in those "dry heat" regions than breathing in that heavy air, you know?