A basic SQLite database containing the sunrise and sunset times for London in 2021 and 2022. As well, there is a JSON file containing the data, a SQL script to create the tables, and SQL queries to check whether the sun has risen or set, and record a successful check for each event per day.
I originally created this as the automatic light/dark mode switching on macOS was often kicking in long after sunset, so I wrote a Keyboard Maestro macro to check the database during potential sunrise and sunset hours, and set the system light/dark mode setting as appropriate.
The "successful checks" table is used as a guard so that the light/dark mode is only switched once per event per day. This means that it won't override any manual change you make after eg it switches because the sun has risen.