How to Read Your Temperature Graph to Understand Your Cycle

The Peri Team

November 6, 2025

Your body tells a story every month — and your temperature graph can help your read it.

How to Read Your Temperature Graph to Understand Your Cycle

Your body tells a story every month — and your temperature graph is one of the clearest ways to read it. By tracking your basal body temperature (BBT) over time, Peri helps you see what’s really happening beneath the surface of your cycle.

🌡️ What Your Temperature Shows

Your body temperature changes in response to hormones:

  • Before ovulation, estrogen keeps your temperature slightly lower.
  • After ovulation, progesterone causes a small but noticeable rise — usually around 0.2–0.5°C (0.4–1.0°F).

This means your temperature graph often shows two distinct phases:

  1. Follicular phase (pre-ovulation): lower, steadier temperatures.
  2. Luteal phase (post-ovulation): a higher plateau of temperatures.

That shift between the two confirms that ovulation has occurred — something apps alone can’t always detect accurately.

🔍 How to Read Your Graph

  • Look for a consistent rise in temperature that stays elevated for several days — that’s your post-ovulation phase.
  • When your temperature stays high for around two weeks and then drops, that     usually signals the onset of your period.
  • If your temperatures stay low and don’t rise, ovulation may not have occurred that cycle.
  • If you notice irregular ups and downs, it could be related to sleep, stress, illness, or hormonal fluctuations (especially common during perimenopause).

💡 Why It Matters

Understanding your temperature pattern helps you:

  • Identify your fertile window and cycle phases,
  • Predict when your period is likely to start,
  • Spot potential hormonal imbalances,
  • See how your body responds to lifestyle changes or hormone therapy.

With Peri, your temperature data isn’t just numbers — it’s context. We translate subtle shifts into meaningful insights about your well-being over time.

Find your best pals in perimenopause.

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Find your best pals in perimenopause.

Pre-order Peri here