Plain English Meaning

The pilot can only see about 150 feet ahead down the runway. That is roughly half the length of a football field. At this visibility, landing is only allowed with the most advanced autoland systems and trained crews.

Full Definition

A Runway Visual Range value of 150 feet, meaning the horizontal distance a pilot can expect to see down the runway from the approach end is 150 feet. In the context of ILS approach categories, RVR 150 feet is the lowest landing minimum associated with Category IIIc operations, which require specially certified aircraft, crew, and ground equipment. RVR is measured electronically by transmissometers or forward-scatter sensors positioned alongside the runway and is reported in feet (or meters internationally).