https://www.theverge.com/circuitbreaker/2017/10/3/16413066/google-home-night-mode-preview-program

Google Home normally has a set volume, so if you turn it up during the day but then use it again at night, it can get too loud for you. To solve those woes, Google Home has gotten a new Night Mode, which is still under early access in Google Home’s preview program and hasn’t yet been released commercially, as first reported by Android Police.

With Night Mode, you can set particular hours or days for Google Home to lower its volume and dim its lights. There’s also a new Do Not Disturb mode, which mutes notification sounds but keeps alarms and timers on.