> A wet-bulb temperature of 95°F (35°C) is the theoretical limit for human survivability for up to six hours of unshaded outdoor exposure

Both the sources you linked say that 35 degrees is the limit in the shade as well.

> It has been thought that a sustained wet-bulb temperature exceeding 35 °C (95 °F)—given the body's requirement to maintain a core temperature of about 37°C—is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan