Your body temperature dips a bit just before your ovary releases an egg. Then, 24 hours after the egg's release, your temperature rises and stays up for several days. Before ovulation, a woman's BBT averages between 97°F (36.1°C) and 97.5°F (36.4°C). After ovulation, it rises to 97.6°F (36.4°C) to 98.6°F (37°C).

What happens to the basal body temperature during ovulation?

Basal body temperature may increase slightly — typically less than a 1/2 degree F (0.3 C) — when you ovulate. Ovulation has likely occurred when the slightly higher temperature remains steady for three days or more. Plan sex carefully during fertile days.

Is your BBT higher or lower during ovulation?

BBT is slightly lower in the follicular phase (the first half of the menstrual cycle), and rises after ovulation and stays raised throughout the luteal phase (the second half of the menstrual cycle) (2,3). This rise in temperature happens in response to progesterone, which is released after ovulation occurs.