In Windows 10 there is a Notification Tile named QUIET HOURS that has many people confused. Quiet Hours are actually a feature that was released in Windows 8, that disables ALL notifications during the set times. This means things like new WiFi hotspots that are detected, or new email in Outlook, or Calendar notifications, will not pop up and annoy you.
In both Windows 8 and 10, the settings for Quiet Hours SHOULD appear under SETTINGS > NOTIFCATIONS. I say SHOULD because in build 10159 of Windows 10 that I am using now, there are not settings for quiet hours. I have reported this to Microsoft and expect a (near) future build will correct this issue.