Enabling Night Mode will reduce the frequency of Announce notifications to one per hour during the hours you specify.
For example, perhaps you do not want hundreds of notifications appearing between the hours of 11pm and 8am. So you can enable Night Mode and enter the Start time and End time for Night Mode to start and finish.
When Night Mode is active:
Night Mode automatically adjusts as Start Time and End Time approaches
Lets assume you have set Night Mode to start at 12.00am and end at 7.00am. With your Feed Frequency as 50 seconds
At approximately 10.30pm (one and a half hours before your Night Mode Start Time begins), Announce will gradually start to increase your default Feed Frequency (eg to 60 seconds, then to 75 seconds, then to 93 seconds and so on) until your Night Mode begins
By the time your Night Mode starts (in this case, 12.00am) the feed frequency will be at approximately 3600 seconds (1 hour). So there will be approximately one Announce notification per hour during night time.
The same is true for when Night Mode is going to end.
For example say you have set Night Mode to end at 7.00am.
One and a half hours before Night Mode ends (in this example 5.30am), Announce will gradually start to decrease the Feed Frequency from 3600. By the time it is 7am, the Feed Frequency will be set back at your required setting (i.e. 50 seconds).