I simply don't understand that virtually none of the weather apps support showing data of the past hours and/or days.

There are so many occasions where I've wanted to have an accurate weather report at the ready from a couple of hours or days before (e.g. during a conversation or when logging the weather conditions during an outdoors activity).

Open-Meteo's forecast API seems to have a Past Days setting, so there's no issue there. I actually think this would generate a unique "selling" point for Bura. Would you be willing to look into this?