<Table> <Tr> <Td> Temperature classification </Td> </Tr> <Tr> <Td> <Table> <Tr> <Td> </Td> <Td> Core (rectal, esophageal, etc .) </Td> </Tr> <Tr> <Td> Hypothermia </Td> <Td> <35.0 ° C (95.0 ° F) </Td> </Tr> <Tr> <Td> Normal </Td> <Td> 36.5--37.5 ° C (97.7--99.5 ° F) </Td> </Tr> <Tr> <Td> Fever </Td> <Td>> 37.5 or 38.3 ° C (99.5 or 100.9 ° F) </Td> </Tr> <Tr> <Td> Hyperthermia </Td> <Td>> 37.5 or 38.3 ° C (99.5 or 100.9 ° F) </Td> </Tr> <Tr> <Td> Hyperpyrexia </Td> <Td>> 40.0 or 41.0 ° C (104.0 or 105.8 ° F) </Td> </Tr> </Table> </Td> </Tr> <Tr> <Td> Note: The difference between fever and hyperthermia is the underlying mechanism . Different sources have different cut - offs for fever, hyperthermia and hyperpyrexia . </Td> </Tr> <Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table> <Tr> <Td> Temperature classification </Td> </Tr>

What is the average temperature for a fever