Ovulation · 6 minute read
Basal body temperature tracking
How to take waking temperature consistently, recognize a pattern, and avoid reading too much into one measurement.
Evidence-informed · Editorial review August 2026 · Links to trusted sources are available in the interactive app
BBT is a resting measurement
Basal body temperature is taken immediately after waking, before getting up or becoming active. Consistent timing and method make the trend more useful than any single number.
Look for a sustained shift
Progesterone after ovulation often produces a small rise that remains for several readings. Because the shift happens after egg release, BBT is better at supporting retrospective confirmation than predicting the fertile window in advance.
Many factors add noise
Fever, disrupted sleep, shift work, alcohol, travel, room temperature, and device differences can affect readings. Wearable temperature is often a deviation from a personal baseline and may not equal oral BBT.