Your Waking Temperature: How It Confirms Ovulation

Cervical fluid tells you when you're in your fertile window which is a 6 day (ish) time frame. Your waking temperature, your basal body temperature, tells you when ovulation has already happened. Ovulation is a short 12-24 hour (ish) time frame within your fertile window.

Why your temperature rises

During ovulation the egg is released from its follicle. That follicle doesn't just disappear. It's main role becomes producing a hormone called progesterone.

Progesterone (pro-gestation) literally warms up your body, by a few tenths of a degree, to support a possible pregnancy. So after you ovulate, your waking temperature rises and stays up until your period, marking your luteal phase.

What it looks like on a chart

Before ovulation, waking temperatures are often in the low 97s, and it's normal for them to move around a little. Then there's a rise, for example from 97.2 to 97.9, then 98, then 98.3.

After the third day of a higher temperature, you can look back and confirm that you ovulated.

Sometimes ovulation comes later than you expected. On a chart, that just means the low temperatures go on longer before the rise. That's information, not a judgment.

How to take it

• Same time every morning, before you get out of bed, before you talk or drink anything.
• A basic basal body thermometer that reads to the tenth of a degree is all you need.
• Write it down right away.

Being sick, drinking alcohol or sleeping badly can push it up, so make a note on those days.

Learn to read your chart

In Fertility Awareness: Read Your Body I walk you through reading your temperature together with your cervical fluid and cervix, with a printable chart to start tonight. The first lesson is free.

This is education, not medical advice. If you're using this to avoid pregnancy and your signs don't line up, consider yourself fertile.