I have never reached 38 (100.4) I will mention this to my doctor but can a fever happen at the exact same time every day and always be gone the rest of the day? I would have assumed if I had some viral infection or chronic disesase it would be elevated most of the day. From what i read about normal body temperature fluctuations I could very well be normal as it follows a cyclic pattern and never breaks through 1F above (98.6)
Typically, a fever becomes significant if it is above 100.4 degrees. Below that, and above the normal, would be considered "low-grade".
With persistent low-grade fevers, further evaluation should be done to determine a source. A chest x-ray, blood and urine cultures, and sputum cultures can all be considered depending on the other symptoms present.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
www.kevinmd.com