Channel reminders
Channel reminders are really cumbersome to use.
Not only you need to type it via command without any feedback, US date format confuse you further, docs found via search engine will make you even more irritated at it’s not giving full example.
This will set reminder on XXXX.03.04 09:00 in your current timezone
/remind #channel "maintenance: XXXX on March 4th at 9am
Sources and useful links: