The phrase "elevated temperature" means that the temperature is higher than normal or higher than what is considered normal or comfortable. Full definition
At elevated temperatures, the corn plant, which under ideal conditions is so extraordinarily productive, goes into thermal shock. (earth-policy.org)
The medieval period represents the longest episode of elevated temperatures outside of the 20th century, although 20th century temperatures clearly exceed those of the medieval period. (pnas.org)
Some dogs may also react with a slightly elevated temperature. (cuteness.com)