After updating my Apple Watch Series 10 to the public release of watchOS 27, Environmental Sound Level measurements became extremely sparse.
Before watchOS 27, with Environmental Sound Measurements enabled, my watch recorded environmental sound data approximately every 30 seconds and the coverage was nearly continuous throughout the day.
After updating the same Apple Watch to watchOS 27, the behavior changed significantly:
- Environmental Sound Level samples are much less frequent
- Large gaps appear between measurements
- Overall daily temporal coverage is dramatically reduced
- The same change is visible both in the Health app and through HealthKit using
HKQuantityTypeIdentifier.environmentalAudioExposure
No relevant settings were changed, and Environmental Sound Measurements are still enabled.
This is important for apps that use Environmental Audio Exposure data for time-based analysis. In my case, I use this data for sleep and nap environment analysis. With the much sparser sampling on watchOS 27, it is difficult to reliably evaluate the acoustic environment during a specific sleep period.
I have also seen other watchOS 27 users reporting similar behavior: https://www.reddit.com/r/watchOSBeta/comments/1wjrdaq/watchos_27_broke_the_noise_monitoring_app/
I submitted a Feedback Assistant report:
FB24837491
Has anyone else observed the same change on watchOS 27?
I’m especially interested in whether this is:
- an intentional change to the sampling or aggregation strategy,
- a HealthKit write-frequency change, or
- a regression in watchOS 27.
If anyone has compared HKQuantitySample.startDate, endDate, sample duration, and sample interval before and after the watchOS 27 update, that data would be very useful for comparison.