價格：免費
檔案大小：20.6 MB
版本需求：需要 iOS 8.0 或以上版本。與 iPhone、iPad 及 iPod touch 相容。
支援語言：英語
When to Sleep counts sleep cycles and tells you when you should fall asleep.
Waking up in the middle of a sleep cycle leaves you feeling tired and groggy, but waking up in between cycles wakes you up feeling refreshed and alert.
When to sleep uses the average times for calculations and suggest best 4 times for you.
支援平台：iPhone, iPad, Apple Watch