Contrary to popular belief, a normal temperature isn't exactly 98.6º F. That's because "normal" isn't the same all the time. In each of us, temperature fluctuates throughout the day, depending on our age, general health, activity, how much clothing we're wearing, and the time of day. Body temperature tends to be lower in the morning and higher between late afternoon and early evening. There's a "normal," healthy temperature range for everyone. For children, it can run between 98.6º F or so and 100.3º F. Most pediatricians consider any thermometer reading above 100.4º F a sign of a fever. Because accuracy can vary depending on the temperature-taking method you're using, mention whether you took your baby's temperature rectally or some other way. Your pediatrician probably will ask anyway.