No. Basal body temperature rises after ovulation, not before: by the time you see the rise, the egg was released 12 to 24 hours ago and the fertile window is practically closed. What it does well is confirm that you ovulated and on which day.
Temperature confirms that ovulation happened, but only after it did. By the time you see the temperature rise, the egg was released 12 to 24 hours ago. The fertile window is practically closed. That's why basal body temperature alone does NOT work for “catching” ovulation.
The reason is biological: the rise is caused by progesterone, produced by the corpus luteum after ovulation. So temperature has one virtue (it confirms ovulation retroactively) and one enormous weakness: by the time you notice the change, the fertile window has already passed. In the book's sequence of signs, temperature is the last to move: it rises 24 to 36 hours after the LH surge, when the mucus is already drying up again.
Temperature can't announce this cycle's ovulation in advance, but it does sharpen your prediction for the next ones. Charted over 3 to 6 cycles, it shows your average day of ovulation and refines the prediction. With 2 to 3 cycles of observation, it confirms that you are ovulating and on which day.
What does NOT work is trying to catch ovulation in the moment: the temperature rises after, not before.
This is also why the tracking apps the book rates most highly don't rely on temperature alone. Sympto-thermal apps combine daily basal temperature with mucus and symptoms and reach 85 to 95% accuracy; apps that only do calendar math reach 50 to 60%.
The most robust method isn't basal body temperature or mucus on its own: it's the combination of the two.
| Sign | What it tells you | When |
|---|---|---|
| Cervical mucus | The window is opening | 3 to 5 days ahead |
| Basal body temperature | The window has closed | 24 hours later |
With both, you have a beginning, an end and confirmation. This is what's formally called the Sympto-Thermal Method, and according to clinical studies it is 97 to 99% accurate for identifying fertility.
This is Chapter 16 of Map to the Positive, in Station II (Attunement). The chapter gives the correct method for taking your temperature, shows how to read the chart and lists the factors that distort it. Around it, Station II covers the signs that come before ovulation (cervical mucus and ovulation tests) and ends with your personal map, which combines them all.
Take 30 days. If it does not give you more clarity than everything you have read for free so far, ask for a refund and you get every cent back. We cannot promise you a pregnancy. We can promise you will not be guessing.
References: Frank-Herrmann P et al. The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple's sexual behaviour during the fertile time: a prospective longitudinal study. Human Reproduction, 2007.