Firstly, what is a BBT chart? BBT stands for Body Basal Temperature. Your BBT is the temperature you take when your body is at a complete rest after a good night's sleep. Throughout the month your BBT will change depending on several factors, including your hormones. It is the lowest measurement of the body’s temperature and used as a baseline. Why is it so important? A BBT chart can tell you so much about what is happening inside your body. For example, it can show if you ha