Small Temperature Shifts, Big Cycle Clues

Your temperature tells a quiet story each month, one that reflects the rhythm of your hormones. Those subtle daily shifts in basal body temperature (BBT) aren’t random; they’re your body communicating what’s happening in your cycle.

Peri focuses on BBT because it’s one of the most reliable windows into how your cycle is truly working. Each rise and dip gives you an insight into what your hormones are doing beneath the surface.

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And during perimenopause, when symptoms can fluctuate and cycles can change from month to month, these temperature patterns become even more meaningful. They bring clarity to a time when your body may feel less predictable.

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Why It Matters

Your temperature shifts for a reason.

• Before ovulation: estrogen keeps temperatures lower and more stable.

• After ovulation: progesterone raises your temperature by about 0.2–0.5°C, creating the gentle rise you’ll see on your graph. That rise is one of the clearest signs that ovulation has likely happened. It’s information your body naturally provides, and Peri helps you read it with confidence.

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Over the month, these small changes add up. The rise after ovulation, the dip before your period, and the irregular fluctuations that are common during perimenopause all reflect what your hormones are doing behind the scenes. Understanding them helps bring order to an experience that may feel unpredictable.

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Instead of relying on apps that guess based on averages, tracking your temperature shows you what’s happening in your body in real time. This helps you understand:

• How your cycle is behaving right now

• Whether ovulation occurred

• How your hormones shift across the month

• What’s changing as you move through perimenopause

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Peri focuses on your daily temperatures because understanding your cycle starts with understanding these shifts. You don’t need perfect charts, just real patterns from your real body.

Getting started

Your first week is simply about watching your pattern begin to appear.
There’s no right or wrong, just gentle observation.

As your graph builds, you’ll start to notice:

• A group of lower temperatures during the estrogen led part of your cycle

• A steady upward shift as progesterone rises after ovulation

• Occasional bumps and dips caused by sleep, stress, illness, or perimenopause

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You don’t need to analyse everything straight away. Just watching the shape of your graph develop is enough. Over time, those daily dots connect into a pattern, and that pattern becomes your personal cycle story.

Peri is here to help you recognise it.

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Important note: Peri is designed to support understanding of your cycle and hormonal patterns using lifestyle data. It is not a contraceptive and should not be used to prevent or plan pregnancy. Peri does not provide medical advice and is not intended to diagnose, treat, cure, or prevent any medical condition. Temperature patterns and insights are for informational purposes only and should not replace guidance from a qualified healthcare professional. Always consult a healthcare provider with questions about contraception, fertility, or your health.