Note: to access the Apple Watch integration, make sure to update your NC° app to version 5.1.0 and phone operating system to iOS16.
When to switch to the Apple Watch
As an existing Natural Cycles user, when you switch devices, the algorithm acknowledges you're using a new measuring device, and it needs to learn about the new temperatures and establish a new coverline. To minimize delaying ovulation detection and causing more Red Days (NC° Birth Control) or Brown Days (NC° Plan Pregnancy), it's best to switch devices at the beginning of a new cycle.
Once you start using Apple Watch, you’ll see a marker on your graph that denotes the day you switched to syncing with your Apple Watch.
What happened to my past data?
Your past temperatures from your other device will still be visible in the app (for example, in the Graph view and the Add Data view); however, the algorithm will no longer consider them when assessing your day-to-day fertility status and detecting ovulation, meaning the temperatures from different devices are not mixed. As a result, your cover line will disappear, and eventually, the algorithm will establish a new cover line based on the temperature data from your Apple Watch.
However, the algorithm will continue to use your previously detected cycle characteristics (such as ovulation days or cycle lengths) in the predictions for the upcoming cycles. All your cycle statistics from your past cycles will also still be visible on the Cycle Insights page.
Please note that the Natural Cycles app will only import Apple Watch data starting from the date when you switched your device to the Apple Watch in the NC° app. Learn more about this here.
There are no changes to Natural Cycles’ effectiveness when using an Apple Watch compared to using the NC° thermometer: Natural Cycles is 93% effective with typical use and 98% effective with perfect use.
If you previously measured with a thermometer, the biggest difference with using an Apple Watch is that you’ll no longer have to remember to measure your temperature every morning. To learn more about how the Apple Watch works with Natural Cycles, please read on here.