This is your lowest body temperature when you are at rest. It is typically measured after you have been asleep for several hours and have just woken up, before you have sex, masturbate, or vape. While a male’s basal body temperature isn’t of much interest, it can be significant for women because before they ovulate, their body temperature is usually between 36.2°C and 36.5°C. The day after a woman ovulates, her basal temperature will increase by at least 0.5°C (36.7°C to 37.1°C for example) and will remain that temperature until she has period. If she tracks her basal body temperature over several cycles, it can be one of the indicators to help predict when a woman will be ovulating. This can be helpful for birth control purposes, as well as for zeroing in on her most fertile days. It does require the use of a specialized thermomether that is specifically for basal body temperature. Also see cervical mucus.