Apple Watch Series 8 uses the temperature sensor to provide women with retrospective ovulation estimates, which can be helpful for family planning purposes. The data also provides improved period predictions, and in watchOS 9, women can receive notifications if a logged cycle history shows a possible deviation like irregular, infrequent, or prolonged periods.
A new Crash Detection feature takes advantage of an updated gyroscope and accelerometer along with an advanced sensor-fusion algorithm to detect severe car crashes and alert emergency services. When a crash occurs, the Apple Watch checks in with the user and if no response is received within a 10-second countdown, emergency responders will be contacted.
Battery life remains the same at up to 18 hours, but it can be extended with a new Low Power Mode added in watchOS 9. With Low Power Mode, the Apple Watch can run for up to 36 hours, but it disables the Always-On display, turns off background heart rate measurements, limits WiFi and cellular connections, and more.
There are both GPS and cellular Apple Watch models, and later this fall, Apple plans to add support for international roaming, allowing Apple Watch owners to connect to a cellular plan when traveling abroad.
The Apple Watch Series 8 is available in aluminum and stainless steel. Aluminum colors include Starlight, Midnight, Silver, and (PRODUCT)RED, while the stainless steel models come in Silver, Graphite, and Gold. Apple has introduced new band colors to go along with the Series 8, and it can be purchased with any available band.