Cogitatio is a suite of systems for Unreal Engine that introduces some commonly found features in games. Some systems are capable of empowering one another, exposing new (or enhancing existing) functionality when present.
air, climate, atmosphere
Aer is a weather and atmospherics system. Originally, night and day cycle functionality was going to be handled in Hora, but weather and atmospherics have such a close relationship with the sun and moon, that it made more sense to move that functionality into Aer. On top of weather, atmospherics, and night/day cycles, other visual (and not-so-visual) elements such as shooting stars are in the works.