There is an unofficial reminder bot on the Fediverse. It can remind you minutes, hours, days, weeks, months or years later. To use it, just mention the bot in a post or reply and include the period you want to be reminded after. For example:

@ remindme @ mstdn.social 1 week

To be reminded in a DM, include the word "dm" in small letters:

@ remindme @ mstdn.social dm 1 week

(Remove spaces in the address to make it work, I've only included spaces to avoid setting off the bot!)

#FediTips

@CorvidCrone Ok, I will remind you on Thursday Apr 18, 2024 at 4:39 PM PDT.