Yes. After ovulation (usually one day after it has occured), progesterone, which is responsible for the increase of basal body temperature, begins to act. The change of basal body temperature caused by progesterone indicates the occurrence of ovulation. The higher temperature phase lasts until the next menstruation. However, if ovulation does not take place, then progesterone is not released, and basal body temperature will not be affected. (Which hormones affect ovulation?)