This depends on a number of things - including the length of time the individual is going to be withstanding the temperature, what they will be wearing and what physical condition they are in.
It also depends on how much humidity is in the air when the person is subjected to the extreme temperature.
In order to get a more specific answer to this question, you would also need to highlight whether you are talking about the internal or external temperature a human body would be able to withstand.
If you are referring to the internal temperature of the human body, studies show most bodies can only survive up to 108 degrees Fahrenheit, or 42 degrees Celcius, as the proteins inside the body begin to die at around 105F.
In terms of the external temperature that humans can withstand, some fire fighters are able to survive in temperatures of up to 200 degrees C while wearing protective clothing. They are trained and conditioned to be able to tolerate high temperatures, though, and are usually in exceptionally good health and physical shape, so it could be assumed that an average person may not be able to withstand such heat as readily.
When considering endurance, if the body is unable to hydrate or replenish lost fluids, and uses what fluids it does have to sweat to try to cool the body down, it is unlikely the body will be able to survive for very long in extreme temperatures.
For example, if a healthy young adult was left outside in temperatures of around 104 degrees Fahrenheit (40 degrees Celcius) without any water, they would not be expected to survive for very long due to dehydration.
It also depends on how much humidity is in the air when the person is subjected to the extreme temperature.
In order to get a more specific answer to this question, you would also need to highlight whether you are talking about the internal or external temperature a human body would be able to withstand.
If you are referring to the internal temperature of the human body, studies show most bodies can only survive up to 108 degrees Fahrenheit, or 42 degrees Celcius, as the proteins inside the body begin to die at around 105F.
In terms of the external temperature that humans can withstand, some fire fighters are able to survive in temperatures of up to 200 degrees C while wearing protective clothing. They are trained and conditioned to be able to tolerate high temperatures, though, and are usually in exceptionally good health and physical shape, so it could be assumed that an average person may not be able to withstand such heat as readily.
When considering endurance, if the body is unable to hydrate or replenish lost fluids, and uses what fluids it does have to sweat to try to cool the body down, it is unlikely the body will be able to survive for very long in extreme temperatures.
For example, if a healthy young adult was left outside in temperatures of around 104 degrees Fahrenheit (40 degrees Celcius) without any water, they would not be expected to survive for very long due to dehydration.