Final answer:
The METAR code 'OVC' indicates that the cloud cover is complete, meaning 8/8 or fully overcast. This can lead to visual difficulties similar to those faced by air traffic controllers during obscured weather conditions.
Step-by-step explanation:
When you see the code 'OVC' in a METAR, which is a type of weather observation report typically used in aviation, it indicates that the cloud cover is quite extensive.
Specifically, 'OVC' stands for 'overcast', which means that the cloud cover is 8/8, or in other words, the sky is fully covered by clouds. This condition can make visual navigation and observations very difficult, similar to how air traffic controllers might struggle during poor visibility conditions at an airport. In such cases, instruments such as radar are used to 'see' through the perpetual cloud layers that obscure the sky.