Normal human body temperature averages 98.6 degrees, but as we know, that can vary from person to person. Body temperature can also be affected by many things other than illness such as: time of day or night, eating, smoking, bathing, drinking, medication like the pill, ovulation and stress. Older people tend to run a little colder in which case 99 degrees could possibly be a sign of illness. In younger people, a temperature over 100.4 is considered an actual fever. (Karen Weintraub for the NYT)
If taking your temperature under your arm pit, add a degree. According to WEBMD, the most accurate body temperature is measured rectally… yikes, tell that to your kids the next time they say they want to stay home from school!!