Mark Gurman, 9to5Mac, is reporting that Apple Watch will include an A5-caliber CPU. Additionally, he shares battery life targets for various use cases. Overall:
Considered separately, the active use app, clock, and fitness numbers sound very low, but the reality is that people will passively wear the Apple Watch for most of the day, actively interacting with it only for short periods of time. That’s why the Watch will be able to last the average user roughly a day on a single charge. We’re told that Apple has been shooting for roughly 19 hours of mixed usage each day, but that the company may not hit that number in the first generation version.