Your basal body temperature is the lowest temperature of your body at rest. You can determine your basal body temperature by taking your temperature as soon as you wake up before you begin moving about. Do not get up to go to the bathroom or get a drink of water. Any activity will raise your BBT, which means you will not have accurate readings.
Ovulation brings about a slight shift in basal body temperature. It’s barely noticeable so in order to discern the slight elevation, you must be tracking your BBT daily.
Unfortunately, you will notice the spike in BBT a day or two after your ovulation has ended. A day or two after you have ovulated, your temperature will raise roughly a half or a full degree and it will stay elevated.
Sometimes women see their BBT rise slightly and think they have ovulated, but it is the consistently elevation that indicates ovulation has happened.
The value of determining your BBT and tracking it is that over several months, you can begin to see a pattern emerging. Tracking your BBT over time will show you the approximate time of ovulation each month. This will help you to know the best days of the month to conceive.