If you’d like to know what time the sun will rise and set in your area, it turns out to be simple to add it to your Org mode agenda. Jon-Michael Deldin shows how.
The ability to display them is already built into the Emacs Diary. All you have to do is specify your latitude/longitude in your init.el and add
* Calendar %%(diary-sunrise-sunset)
to one of the files in your agenda list. See Deldin’s post for the details including how to get your lat/lon if your computer or phone won’t tell you.