Cycle clarity, even when your cycles aren't predictable

Daysy fertility tracker resting on wooden bedside table showing USB charging port and teal LED indicator
Daysy fertility tracker resting on wooden bedside table showing USB charging port and teal LED indicator

When your cycle is irregular, most apps and tools rely on a pattern you don't have.

When your cycle is

irregular, most apps

and tools guess.

Daysy doesn't predict.

It reads your real waking temperature each morning,
so you can see where you are in your cycle one day at a time.

It reads your real temperature each
morning to help you understand where
you are in your cycle, one day at a time.

See how Daysy works for irregular cycles


★★★★★ Rated 4.7/5
Trusted by 500,000+ women worldwide

  • 99.4 % accuracy

  • Clinically validated

  • Hormone free

  • Used by over 500K women worldwide

  • 2 year warranty

  • 30-day risk-free return

  • For women with PCOS

For women with PCOS,

cycle tracking can feel like

guesswork

For women with PCOS,

cycle tracking can

feel like guesswork

  • Apps forecast based on averages that don't apply to you

  • OPKs rely on LH, which is often chronically elevated with PCOS — giving false positives, not answers.

  • "Tracking everything" becomes a mental load

  • You end up feeling like your body is the problem.

Your cycle may be irregular. Your insight into it shouldn't have to be.

  • For irregular cycles

Yes - Daysy works

if your cycle is irregular.

Yes - Daysy can

support you if your

cycles are irregular

Here's what that looks like in real life:

It doesn't predict from past cycles. It responds to what your body does today.

It handles varying cycle lengths. A 29-day cycle one month and a 38-day cycle the next won't throw off the algorithm.

It supports cycles between 19 and 40 days. If yours are consistently longer than 40 days, we recommend speaking with a clinician before purchasing — Daysy isn't a replacement for medical investigation in that case.

Expect more yellow days in your first 1–2 cycles. That isn't the device failing — it's the algorithm being honest while it learns your pattern. By cycle 2 or 3, most users have a clearer, more consistent picture.

Daysy fertility tracker on grey stone surface showing full device profile, blue and green LED indicators and USB charging port

With PCOS, LH is often chronically elevated - which is why OPKs can give multiple false positives in a single cycle, and why apps trained on average cycles simply don't apply.

Daysy bypasses both. It reads the temperature shift your body makes around ovulation across cycle lengths within Daysy's 19–40 day range, no matter how much your cycle varies from month to month.

Daysy won't diagnose PCOS, but the patterns it reveals over time give you and your doctor data worth paying attention to.

See pricing and full details
Daysy app BBT chart showing ovulation detected on cycle day 7 — lower temperatures before ovulation and temperature rise after, with daily reading of 36.15°C at 07:03 AM

Designed for real cycles

Daysy adapts to
your rhythm - not the other
way around Daysy adapts to
your rhythm - not the
other way around

A simple 60-second temperature reading each morning gives
Daysy the one signal that reliably reflects what your hormones are
doing: your waking temperature.


Over time, that signal becomes a pattern.
So you can understand your real rhythm.

01

Take a 60-second temperature reading each morning

Your waking temperature shifts across the cycle in
small but meaningful ways. Your waking temperature shifts
across the cycle in small but
meaningful ways.

02

Daysy analyses your pattern

It considers your reading, your past data, and any
disturbances like travel, illness, or disrupted sleep. It considers your reading, your
past data, and any disturbances
like travel, illness, or disrupted sleep.

03

Check your daily status

Three lights show where you are in your cycle — green (non-fertile), red (fertile), yellow (learning your pattern). Sync the app for charts, trends, or notes if you want deeper insight.

  • Trusted by 500,000+ women worldwide

For women who are

tired of guessing

  • Before, I was never exactly aware of when I was ovulating. Now I always know exactly where I am right now.

    Diana K.
    Verified buyer

  • Daysy reliably detects my ovulation and shows me the fertile window with a few days of buffer. After five months hormone-free, my migraine has improved significantly.

    Kunde
    Verified buyer

  • Daysy has been super accurate with everything so I confidently use it. It's a bit of an investment up front but you have zero monthly fees.

    Jenn
    Verified buyer
  • What women notice

What women notice when they start using Daysy

Irregular cycles stop feeling like a mystery. You start seeing a rhythm.


You can plan with more confidence. Seeing where today sits in your cycle brings steadiness.


You stop feeling "too irregular." You get a tool that works with your body as it is.


It's one simple thing to do. One morning reading, and you're done.


Many women find Daysy helpful specifically because it gives shape to a cycle that previously felt shapeless.

Why temperature works better

Temperature
tells a clearer story than
predictions ever can Temperature tells a
clearer story than
predictions ever can

Most tools try to work out your fertile window by
guessing what your body might do.


Daysy works by observing what your
body is actually doing right now.

App & Calendars

  • Predict from generic past cycles
  • Expect regularity
  • Struggle with PCOS patterns

OPKs

  • LH is often chronically elevated with PCOS
  • Multiple false positives in a single cycle
  • Tracking window is unclear when LH doesn't peak cleanly

Daysy

  • Uses your waking temperature
  • Responds to what your body is doing today
  • Built for cycles between 19 and 40 days

  • 99.4 % accuracy

  • Clinically validated

  • Hormone free

  • Used by over 500K women worldwide

  • 2 year warranty

  • 30-day risk-free return

1 6

Ready for Clearer Days?


Bring clarity to an unpredictable cycle

HSA Class A
medical device 30-day
risk-free return Free delivery
across Singapore
Rated 4.7/5 by the global Daysy community Rated 4.7/5 by the Daysy community
$449.00
Or 3 x $150 with Atome
Sale Sold out
Secure checkout
One time purchase
No subscription

"I am irregular and I have only had one cycle, and it has already detected 11 green days. I was right to invest that money."

A.

verified Daysy user

View full details
  • CE certification icon indicating compliance with European medical device standards

    CE
    certified

  • HSA Singapore certification icon indicating registered medical device status

    HSA Class A
    medical device

  • FDA classification icon indicating medical device regulatory status

    FDA
    classified

  • 2-year
    warranty

  • Package delivery icon with checkmark indicating successful delivery

    Free delivery
    (3 days)

  • 30-day risk-
    free return

From Stemba

A note from Stemba

Irregular cycles can create uncertainty, frustration, and a lot of unanswered questions.

You deserve clarity that fits into your real life - not more noise, pressure, or guesswork.

We chose Daysy because it gives women a simple, evidence-based way to understand their bodies with more confidence and less overwhelm.

Woman sitting on bed holding a cup of coffee and looking relaxed in soft morning light
  • FAQ

Common questions about Daysy and irregular cycles

If something doesn't feel clear
(or you just want someone to walk through
it with you), we're here.


You're always welcome to ask

Whatsapp Stemba Support
Chat with Luna

Yes — Daysy is built to handle cycle variation. Because it reads your morning temperature rather than predicting from averages or detecting LH, the patterns that throw off apps and OPKs don't affect it the same way. This includes women with PCOS, though cycles need to fall within the 19–40 day range. Expect more yellow days in the first one to three cycles as Daysy learns your rhythm — that's normal. Over time it builds a picture of your cycle that's based on your data, not someone else's averages.

With irregular cycles, Daysy typically needs one to three cycles to build a reliable pattern. You'll likely see more yellow days in the first cycle — that's Daysy learning your rhythm, not a sign something's wrong. Most women in this situation have a much clearer picture by cycle three, as the algorithm adapts to your specific temperature signals.

Daysy handles cycle variability well. Its algorithm evaluates each cycle individually rather than averaging your history — so it adapts whether your cycle runs 28 days one month and 38 days the next. That's what makes it different from apps that predict based on past averages: Daysy responds to what your body is doing now, not what it did last time.

Daysy works for cycles between 19 and 40 days. If your cycles regularly exceed 40 days, it's outside the range Daysy is designed for — the algorithm needs data within that window to classify with confidence. For cycles consistently above 40 days, we recommend speaking with a clinician before purchasing. When cycle length sits outside typical range, clinical investigation gives you better answers than any tracking device can.
If your cycle occasionally runs longer but isn't consistently above 40 days, that's a different picture — Daysy can still build a reliable pattern for you.

Apps predict your fertile window using cycle averages — which is exactly what breaks down when your cycles aren't regular. OPKs detect an LH surge, but hormonal patterns with PCOS or irregular cycles can produce false positives or surges that don't lead to ovulation. Daysy works from a different signal: the small temperature rise that happens after ovulation. That signal shows up in your real data whether your cycle is 26 days or 38 days. Over one to three cycles, Daysy builds a picture of your rhythm — not a forecast based on someone else's.

Yes. The DaysyDay app is free to download and free to use with your Daysy device — no subscription, no monthly fee. Your S$449 is a one-time purchase that covers the device and the app.

Daysy doesn't diagnose conditions like PCOS or endometriosis — that's a clinician's job, not a cycle tracker's. But the temperature patterns Daysy reveals over time can give you, and your doctor if you choose to share them, useful data about your cycle. If you notice persistent irregularities, that data is worth discussing with a clinician. Many women find Daysy helpful specifically because it gives shape to a cycle that previously felt shapeless.

If something doesn't feel clear
(or you just want someone to walk through
it with you), we're here.


You're always welcome to ask

Whatsapp Stemba Support
Chat with Luna