The tower determines which runway is used at an airport. This is primarily based on the prevailing wind (direction and strength), which can be determined using METAR and TAF. If local specifics are to be considered (e.g. maximum tailwind components for a runway), this can be found in the respective airport SOP.

The tower determines the direction of operation based on where the most traffic is on the Apron.

The approach controller determines which runway is in use depending on the incoming traffic.