Receive retrospective ovulation estimates on Apple Watch
Apple Watch Series 8 or later, and all models of Apple Watch Ultra, can use wrist temperature data to estimate the likely day of ovulation after it has occurred and improve period predictions.
Here's what you need
An Apple Watch Series 8 or later, or any model of Apple Watch Ultra.
Cycle Tracking must be set up with fertility predictions enabled and no ongoing cycle factors logged.
Sleep must be set up with Track Sleep with Apple Watch and Sleep Focus enabled.
Sleep Focus must be enabled for at least 4 hours a night for 5 nights to get accurate wrist temperature data.
View your ovulation estimates
When an estimate of when you likely ovulated is available, you’ll receive a notification on your Apple Watch or iPhone. In the Health app on iPhone or Cycle Tracking app on Apple Watch, your ovulation estimate appears as a light purple oval in your fertile window.
How retrospective ovulation estimates work
Apple Watch Series 8 or later, and all Apple Watch Ultra models, use wrist temperature data to detect the biphasic shift, which is an increase in temperature that often occurs after ovulation. Advanced algorithms use wrist temperature data and logged cycle data to estimate the day ovulation likely occurred.
Get the best results
Accurately log your period in Cycle Tracking.
Wear your Apple Watch to sleep each night with Sleep Focus enabled.
Make sure your Apple Watch fits just right. The band should be snug but comfortable, and the back of your Apple Watch needs to be touching your wrist.
Wear your Apple Watch Series 8 or later, or any model of Apple Watch Ultra, regularly for at least 2 cycles to gather nightly wrist temperature data. If your watch is repaired, or if you pair and use a new watch, you'll need to wear your new watch for at least 2 cycles to receive a new ovulation estimate.
Additional factors
Various factors may have an impact on the availability of ovulation estimates.
There may not be enough wrist temperature data to estimate ovulation for a cycle. It takes about 2 menstrual cycles of wearing Apple Watch to sleep each night with Sleep Focus enabled for ovulation estimates to be available.
Wrist temperature data can also be impacted by certain environmental or physiological factors.
Ovulation may have occurred without a biphasic shift, or the shift in temperature may have been too low to provide an estimate.
Ovulation may not occur every cycle.
Things you should know
Cycle Tracking should not be used as a form of birth control.
Data from Cycle Tracking should not be used to diagnose a health condition.
Ovulation estimates are estimates only, and do not guarantee that ovulation has occurred.
Ovulation estimates are only available in certain countries and regions. Learn where the feature is available.