Why is my temperature 97.5?

May be normal. A person who always measures his or her temperature to be 97.5-98.6 degrees when not ill, may be normal at that measurement. At his annual check-up, or at his next blood test, he can ask his doctor to order a thyroid hormone test to be sure it is not low (low thyroid lowers body metabolism/temp.). A person with ill symptoms and lower than usual temp. Should see his doctor soon for an evaluation.